Showing papers on "Curie temperature published in 1984"
TL;DR: In this paper, a new compound composed of Nd, Fe, and a small quantity of B (about 1 wt. %) has been found, which has a tetragonal structure with lattice constants a=0.880 nm and c=1.221 nm.
Abstract: A new compound composed of Nd, Fe, and a small quantity of B (about 1 wt. %) has been found, which has a tetragonal structure with lattice constants a=0.880 nm and c=1.221 nm. This phase, which has the approximate composition, 12 at. % Nd, 6 at. % B and balance Fe, possesses remarkable magnetic properties. From the approach to saturation an anisotroy constant of about 3.5 MJ/m3 can be calculated, while saturation magnetization amounts to 1.35 T. The magnetization versus temperature curve shows a Curie temperature of 585 K, which is much higher than those of the Fe and light rare earth binary compounds. Based on the new compound, sintered permanent magnets have been developed which have a record high energy product. Permanent magnet properties and physical properties of a typical specimen which has the composition Nd15B8Fe77 are as follows: Br =1.23 T, HcB =880 kA/m, HcI =960 kA/m, (BH)max =290 kJ/m3, temperature coefficient of Br =−1260 ppm/K, density=7.4 Mg/m3, specific resistivity=1.4 μΩm, Vickers hardn...
2,525 citations
TL;DR: In this article, a martensitic phase transition to a complex tetragonal structure occurs on cooling below 202 K. Reasons for the structural transformation are discussed, and details of the low temperature crystallographic superlattice and magnetic structure are determined.
Abstract: Magnetization, magnetic susceptibility, optical microscopy, X-ray diffraction and neutron diffraction measurements have been made on a quenched sample of Ni2MnGa. Room-temperature neutron diffraction patterns indicate a highly ordered Heusler alloy, L21 type, structure. The alloy is ferromagnetic with a Curie temperature of 376 K, and a magnetic moment of 4·17μB largely confined to the Mn sites, but probably with a small moment <07·3μB associated with the Ni sites. A martensitic phase transition to a complex tetragonal structure occurs on cooling below 202 K. Neutron diffraction oscillation photographs taken using the D12 facility at Institut Laue Langevin, Grenoble, and low-temperature powder neutron diffraction data enabled details of the low temperature crystallographic superlattice and magnetic structure to be determined. Reasons for the structural transformation are discussed.
1,048 citations
TL;DR: In this paper, structural and metallographic studies were carried out on the Nd-Fe-B alloy system as well as the nd-fe-B tetragonal compound on which record high energy magnets have been developed using a powder metallurgical technique.
Abstract: Structural and metallographic studies were carried out on the Nd-Fe-B alloy system as well as the Nd-Fe-B tetragonal compound on which record high energy magnets have been developed using a powder metallurgical technique. The study on the new magnet has also been extended to other R-Fe-B componds containing various rare earths (R) and to R-Fe-Co-B alloys. The results are as follows; (1) The sintered Nd-Fe-B magnet is composed of mainly three phases, the Nd 2 Fe 14 B matrix phase plus Nd-rich phase and B-rich phase ∼ Nd 2 Fe 7 B 6 ) as minor phases. (2) Nd 2 Fe 14 B has the space group of P4 2 /mnm. The crystal structure of this phase can be described as a layer structure with alternate stacking sequence of a Nd-rich layer and a sheet formed only by Fe atoms. The sheet of Fe atoms has a structure similar to the σ-phase found in Fe-Cr and Fe-Mo systems. (3) The Nd-rich phase containing more than 95 at.% Nd, 3∼5 at.% Fe and a trace of B has fcc structure with a=0.52 nm. This phase is formed around grain boundaries of the matrix phase. Nd 2 Fe 7 B 6 phase has an one-dimentional incommensurate structure with a=a o and c\simeq8 C o , based on a tetragonal structure with a o =0.716 nm and c o =0.391 nm. (4) In the as sintered Nd 15 Fe 77 B 8 alloy periodic strain contrasts are observed along grain boundaries, which disappear after annealing at 870K. This may be related to the enhancement of the intrinsic coercivity of the sintered magnet by post sintering heat treatment. (5) Stable R 2 Fe 14 B phases are formed by various rare earths except La. Of all the R 2 Fe 14 B compounds, Nd 2 Fe 14 B has the maximum saturation magnetization as high as 1.57 T. Dy and Tb form R 2 Fe 14 B phases with the highest anisotropies. Small additions of these elements greatly enhance the coercive force of the Nd 2 Fe 14 B base magnet. (6) Partial replacement of Fe by Co raises the Curie temperature of the Nd 2 Fe 14 B compound, which improves the temperature coefficient of the remanence of the magnet. But the intrinsic coercive force is decreased by the Co addition.
706 citations
TL;DR: In this article, the selection of materials and expected magnetocaloric effects for magnetic cooling applications at elevated temperatures (400-800 K) were discussed for rare earth transition metal compounds such as Sm2Fe17−xCox for this task.
Abstract: Selection of materials and expected magnetocaloric effects are discussed for magnetic cooling applications at elevated temperatures (400–800 K). Various considerations result in the selection of rare earth‐transition metal compounds such as Sm2Fe17−xCox for this task. These materials offer a wide range of suitable magnetic ordering temperatures as a function of x. They also show relatively high effective magnetic moments per volume. Molecular field models are developed for analytically predicting entropy changes at and above the ordering temperature. Concomitant adiabatic cooling ΔT is accordingly computed for these compounds near the ordering temperatures. It is found that for a family of compounds ΔT values increase somewhat with increasing ordering temperatures due to the decreasing influence of the lattice heat capacity at higher temperatures. Adiabatic cooling of ΔT=−7.5 K at 70 kOe to ΔT=−9.2 K at 70 kOe is predicted for materials Y2Fe17−xCox near their Curie points of 300 and 600 K, respectively (c...
695 citations
TL;DR: In this article, the lattice constants and the X-ray density of ternary tetragonal compounds of the composition R 2 Fe 14 B were determined for R = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu.
249 citations
Patent•
30 Apr 1984
TL;DR: In this article, a switching device is provided to connect one or the other of the layers to be energized from a constant current source, and the device autoregulates in the region of the Curie temperature of the selected layer.
Abstract: A multiple temperature autoregulating heater comprises a laminate of a conductive material, a first ferromagnetic layer on a surface of the conductive material and a second ferromagnetic layer insulated from the first layer. The layers have different Curie temperatures. A switching device is provided to connect one or the other of the layers to be energized from a constant current source. The device autoregulates in the region of the Curie temperature of the selected layer. The conductive material may be non-magnetic (copper) or a low resistivity ferromagnetic material having a Curie temperature well above the Curie temperatures of the autoregulating layers. In the latter case, a thin layer of copper or the like may be interposed between the surface and the conductive ferromagnetic material to further increase conductivity. The device may be provided with multiple ferromagnetic layers to provide multiple different autoregulating temperatures.
184 citations
TL;DR: The magnetic properties of rapidly quenched FeRM alloys where R=La,Y,Pr,Nd,Gd and M=B,Si,Al,Ga,Ge have been investigated over a wide range of chemical compositions as discussed by the authors.
Abstract: The magnetic properties of rapidly quenched FeRM alloys where R=La,Y,Pr,Nd,Gd and M=B,Si,Al,Ga,Ge have been investigated over a wide range of chemical compositions. The samples are generally magnetically soft in the as‐quenched state. Magnetic hardening is produced by annealing the samples around 700 °C. The best properties have been obtained in samples containing Pr and Nd together with B and Si. An energy product of 13 MGOe and a coercive field of 15 kOe have been obtained in a Fe76Pr16B5Si3 sample. The higher Fe content samples appear to be more promising with a potential energy product of 49 MGOe. Thermomagnetic data show that a structural transformation takes place upon heating the samples to 700 °C. The Curie temperature of the as‐quenched phase is around 160 °C while that of the new phase is around 320 °C. Transmission electron microscope studies show fine precipitates (∼100 A) dispersed in a matrix of different chemical composition. X‐ray and electron diffraction data indicate that the precipitates have the Fe21R3B tetragonal structure. The high anisotropy of this phase together with its fine size and distribution give rise to the observed high coercive fields.
153 citations
TL;DR: In this paper, the authors discuss the "disordered local moment" (DLM) picture of metallic magnetism and derive a spin density functional approach based on the spin Density Functional Approach.
152 citations
TL;DR: In this paper, self-consistent spin-polarized energy-band calculations are used to explain the trends in the ferromagnetic moments of transition-metal alloys.
Abstract: Self-consistent spin-polarized energy-band calculations are used to explain the trends in the ferromagnetic moments oftransition-metal alloys. It is demonstrated that a large amount of magnetization data become interpretable by using the generalized Slater-Pauling curve recently introduced by Williams et al. The discussion includes Heusler alloys of both L21 and Clb structure for which exchange constants and hence the Curie temperatures can be estimated theoretically. CoMnSb is treated in detail and is shown to belong to the class of half-metallic ferromagnets first discovered by de Groot et al. Also included will be Fe3Cr and Au4V which represent interesting examples of itinerant ferromagnetism.
145 citations
TL;DR: In this article, a conformational model of tilting trans structure containing skew linkages was proposed to explain the structural changes in ferroelectric phase transition of vinylidene fluoride-trifluoroethylene (VDF-TrFE) copolymer.
126 citations
TL;DR: Several pnictides with the filled skutterudite (LaFe 4 P 12 type) structure were investigated by X-ray diffraction, magnetic susceptibility and electrical conductivity measurements and Mossbauer spectroscopy.
TL;DR: In this article, the Curie temperature of the Fe 1-x Cu x alloys was investigated by X-ray diffraction and magnetization measurements and the mixed phase of bcc and fcc.
Abstract: High concentration Fe 1- x Cu x alloys have been obtained by rf sputtering technique and investigated by X-ray diffraction and magnetization measurements. The bcc phase is extended over the region with x =0–0.4, while the fcc phase with x =0.6–1.0. For x =0.4–0.6, we have the mixed phase of bcc and fcc. The lattice constant of bcc phase increases slightly and that of fcc phase decreases with increasing x . In the bcc alloys, the average magnetic moment decreases with increasing x and deviates upwards from the simple dilution law. In the fcc alloys, the magnetic moment also decreases with increasing x but it deviates downwards from the simple dilution law. The Curie temperature, T c , of the Fe 1- x Cu x alloys decreases abruptly with increasing x : T c is higher than 750 K for the bcc alloys, while it is lower than 320 K for the fcc alloys and become 0 K at about x =0.92.
TL;DR: In this article, the formation regions of Fe7C3 and Fe3C were determined at high temperature and high pressure in the iron graphite system, and the results showed that the substitution of other metals (Cr, Mo and W) for iron in these carbides leads to changes in the thermal stabilities and the magnetic properties.
Abstract: The formation regions of Fe7C3 and Fe3C were determined at high temperature and high pressure in the iron-graphite system. Fe7C3 formed at relatively higher pressures and Fe3C at lower pressures. Both Fe7C3 and Fe3C were isolated from coexisting excess carbon powders by a magnetic method. Fe7C3 had a Curie point of 250° C and a saturation magnetization of 120 emu g−1 at room temperature and Fe3C had those of 210° C and 125 emu g−1. Fe7C3 decomposed to Fe3C and carbon at 600° C, but to α-Fe and carbon at 700° C at atmospheric pressure, and Fe3C to α-Fe and carbon at 700° C. The substitution of other metals (Cr, Mo and W) for iron in these carbides leads to changes in the thermal stabilities and the magnetic properties.
TL;DR: In this paper, the authors present experimentale du comportement des bandes non occupees dedoublees par echange dans les ferromagnetiques a l'approche de la temperature de Curie.
Abstract: Etude experimentale du comportement des bandes non occupees dedoublees par echange dans les ferromagnetiques a l'approche de la temperature de Curie. En utilisant la spectroscopie d'isochromate a spin polarise on observe l'apparition d'etats de majorite et de minorite au voisinage du point H dans Fe cubique centre quand la temperature s'eleve. Ceci fournit l'evidence d'un etat de bande en train de s'effondrer
TL;DR: In this article, the authors measured the electrical resistivity and magnetic susceptibility of single crystals to study the dense Kondo phenomenon and found that the dilute Kondo state is continuously connected to the dense kondo state as a linear function of cerium concentration in the paramagnetic region.
Abstract: We have measured the electrical resistivity and the magnetic susceptibility of Ce x La 1- x Al 2 ( x =0–1) single crystals to study the dense Kondo phenomenon. The magnetic resistivities per molar cerium, which result from the combined effect of the crystalline field and the Kondo scattering, are found to be almost the same at higher temperatures than ca. 50 K. The Curie temperature of ca. 30 K and the effective Bohr magneton of ca. 2.5 µ B are also independent of the concentration of cerium ion. These data show that the dilute Kondo state is continuously connected to the dense Kondo state as a linear function of cerium concentration in the paramagnetic region.
TL;DR: In this article, a copolymer of VF2 with tetrafluoroethylene was examined and the Curie transition was detected in the vicinity of 110-115°C, where the dielectric peaks associated with this transition are clearly separated from any contribution of bulk conduction.
Abstract: To confirm and extend further our previous prediction of a Curie transition in PVF2, we examined a copolymer of it with tetrafluoroethylene (81 mol % VF2). The tetrafluoroethylene units serve to render this copolymer equivalent to PVF2 of a slightly increased head‐to‐head content. Contrary to other reports, we have detected a Curie transition in this material using x‐ray diffraction, dielectric, and calorimetric techniques. The ferroelectric‐to‐paraelectric transformation is barely perceptible because it begins at ∼122 °C (which is only slightly below the main melting point) and is rapidly overtaken by melting. However, the reverse (paraelectric‐to‐ferroelectric) transition is detected unequivocally in the vicinity of 110–115 °C because of the metastability of the paraelectric phase that crystallizes from the melt. The dielectric peaks associated with this Curie transition are clearly separated from any contribution of bulk conduction. The characteristics of this transition are analogous to those found in copolymers of VF2 with trifluoroethylene and thus indicate that such ferroelectric behavior is inherent to PVF2 and does not reflect influences of any particular comonomer.
TL;DR: In this article, the primary crystalline phase developed in glass-ceramics in the system PbO-BaO-TiO2-B2O3 was investigated.
Abstract: The primary crystalline phase developed in glass-ceramics in the system PbO-BaO-TiO2-B2O3 was investigated. X-ray diffraction and dilatometry were used to identify the primary phase as essentially pure PbTiO3. Peak shifts observed in X-ray diffraction patterns resulted from lattice strain due to crystal clamping, and not from (Pb, Ba) TiO3 solid solution formation. Lattice strain was found to increase as the glass-transition temperature of the residual glass increased above the Curie temperature of PbTiO3.
TL;DR: In this paper, single-phase LaNi1-xMnxO3 samples in the compositional range 0 0.05 to 0.50 K were used to investigate the ferromagnetic spin glass properties of LaNi 1-mnx oxide.
Abstract: Single-phase LaNi1-xMnxO3 samples in the compositional range 0 0.05, but any motional enthalpy appears to remain small ( Delta Hm approximately=0). The x=0.1 sample exhibits ferrimagnetic spin glass behaviour below 40K, and the ferromagnetic interactions increase with manganese concentration. The oxide with x=0.50 is ferromagnetic with a well defined Curie temperature.
TL;DR: Ferrimagnetic resonance (FMR) measurements were made at room temperature on polished spheres of about 0.3 mm size at frequencies between 3 GHz and 90 GHz as discussed by the authors, and the observed FMR linewidth ΔH can be described by a frequency independent two-magnon scattering contribution ranging between 5 Oe and 10 Oe.
TL;DR: In this article, it was shown that the Curie point of this Ti-stabilized SmFe5 phase should be greater than 600°C and the demagnetizing field in the plane of the thin film samples should be used in obtaining the inplane B field.
Abstract: Samples of the Sm‐Fe system have been directly crystallized onto heated substrates by selectively thermalized sputtering. Films of the pure Sm‐Fe system exhibit only the 1–2, 1–3, and 2–17 phases which correspond to the bulk system. But samples synthesized with certain third element additions of oxygen and titanium exhibit a metastable phase at a composition corresponding to a 1–5 Sm–Fe compound. These samples exhibit well defined and reasonable sharp x‐ray diffraction patterns. Room‐temperature intrinsic coercive forces of 6.2 kOe and static energy products of 5.5 MG Oe have been observed. These results are for the demagnetizing field in the plane of the thin film samples and no demagnetizing factor has been used in obtaining the inplane B field. Samples synthesized in the presence of an inplane magnetic field at 600 °C exhibit an inplane anisotropy which indicates the Curie point of this Ti‐stabilized SmFe5 phase should be greater than 600 °C. Film samples of the pure Sm‐Fe system which do not show a metastable phase generally have low intrinsic coercive forces and consequently low energy products.
TL;DR: In this paper, an analysis of regenerative thermomagnetic generators with perfect regeneration has been performed for three working materials: iron, gadolinium, and Ho69Fe31.
Abstract: Thermomagnetic generators allow direct conversion of heat energy to electrical energy. Temperature cycling about or near the Curie temperature causes changes in magnetization, resulting in time variant magnetic flux and induced voltage in a surrounding conductor. Numerical analyses of regenerative thermomagnetic generators with perfect regeneration have been performed for three working materials: iron, gadolinium, and Ho69Fe31. Power density above 20 W/kg of shunt material and efficiency approaching Carnot limits are possible over temperature differences of 50 K. Analytical studies performed during the 1950s predicted maximum power density less than 7 W/kg and efficiency less than 1% for nonregenerative cycles.
TL;DR: In this paper, the same authors investigated the optical Faraday rotation in the temperature range 8-300 K at 0.6328 μm wavelength in a magnetic field up to 20 kOe.
Abstract: On three fluorides CeF3, NdF3, and PrF3 accurate susceptibilities measurements are reported from 2 up to 300 K under a magnetic field applied along the c axis. On the same samples, the optical Faraday rotation has been investigated in the temperature range 8–300 K at 0.6328 μm wavelength in a magnetic field up to 20 kOe. The reciprocal susceptibilities χ−1(T) follow a Curie Weiss law for T>100 K; the observed values of the paramagnetic Curie temperature are − 56 K (PrF3), − 114 K (CeF3), and − 26 K (NdF3). For T 77 K. (V and χ are expressed in deg cm−1 Oe−1 and in μB mol−1 Oe−1, respectively.) On one hand for NdF3 and PrF3, it ...
TL;DR: In this article, the binding energy is about 1 eV per hydrogen and the corresponding increase in volume per absorbed hydrogen is approximately 0.5 A3, and the hydrogen diffusion constants have been estimated from the mechanical relaxation, and activation energies of order 0.4 eV have been deduced.
Abstract: Melt spun and sputtered amorphous alloys from the a FexM100−x series with M=Y or Zr can be electrolytically hydrogenated up to a maximum of about 3 hydrogens per M, while retaining their mechanical integrity. Hydrogen uptake has been monitored in situ during hydrogenation by following the increase in length of the melt‐spun ribbons. Values of up to 7% have been found, and the corresponding increase in volume per absorbed hydrogen is approximately 0.5 A3. Hydrogen diffusion constants have been estimated from the mechanical relaxation, and activation energies of order 0.4 eV have been deduced. The binding energy is about 1 eV per hydrogen. Desorption at elevated temperatures preceeds crystallization of the alloys studied, and the hydrogen‐loaded materials retain much of their charge at room temperature for periods of order one year. Iron‐rich yttrium alloys have a moment close to 2 μB/Fe, but they are asperomagnets, the iron moments freezing in a random noncollinear arrangement which possesses a net moment,...
TL;DR: In this article, a site preference mechanism is used to order the bismuth ions via the site preference process, which is characterized by a strong dependence on the growth conditions such as the melt composition and the supercooling allowing the variation of K √ min{u}max{g} in the range O Jm-3.
Abstract: Epitaxially grown bismuth-substituted iron garnet films of composition R 3-x Bi x Fe 5-y M y O 12 with x \leq 2.5 (R=Y,Gd,Lu,Yb and M = Al,Ga,Si) are considered with respect to the temperature and concentration dependence of their magnetic and magneto-optical properties. In particular, the magnetization, Curie temperature, uniaxial anisotropy, optical absorption and Faraday rotation reveal pronounced changes with increasing bismuth content. Special attention is paid to the control of the uniaxial growth-induced anisotropy caused by the ordering of the bismuth ions via the site preference mechanism. This ordering process is characterized by a strong dependence on the growth conditions such as the melt composition and the supercooling allowing the variation of K\min{u}\max{g} in the range O Jm-3. The magneto-optical properties exhibit a linear increase with increasing bismuth content.
TL;DR: In this article, self-consistent para and ferromagnetic LMTO energy band results are presented for Fe (bcc structure), Co (hcp and fcc structure) and Ni (fcc structure).
TL;DR: The saturation magnetization and the magnetocrystalline anisotropy were measured on single crystals in the solid solution series SrZn 2-x Co x Fe 16 O 27 (SrZn2-xCo x -W) at 298 K and 6 K Lattice constants and Curie-temperatures are also given as a function of the composition as discussed by the authors.
Abstract: The saturation magnetization and the magnetocrystalline anisotropy were measured on single crystals in the solid solution series SrZn 2-x Co x Fe 16 O 27 (SrZn 2-x Co x -W) at 298 K and 6 K Lattice constants and Curie-temperatures are also given as a function of the composition The magnetocrystalline anisotropy changes from uniaxial to planar dependent on temperature and cobalt substitution at x \approx 05 for 6 K and x \approx 085 for 298 K The six-fold anisotropy in the basal plane of the planar W-hexaferrites increases strongly with increasing cobalt content Crystals with a low Co substitution (x = 033 and 067) have an anomalous discontinuity in their hard direction magnetization curves; indicating a first-order magnetization process
TL;DR: In this article, the magnetic structure of holmium has been studied by neutron diffraction techniques and the magnetic form factor has been measured and compared with relativistic atomic calculations, and evidence for asphericity in the magnetization density is presented and discussed.
Abstract: The magnetic structure of high purity single crystals of holmium has been studied by neutron diffraction techniques. Although the general characteristics of the magnetic structure have been found to agree with earlier measurements, some discrepancies have been resolved and new features have been observed. The magnetic form factor has been measured and compared with relativistic atomic calculations. The low temperature structure (T<20 K) is that of a conical ferromagnet with wave vector (1/6)(2π/c) along the c axis. The basal plane moment is 9.7 μB and the c‐axis ferromagnetic component is 1.6 μB at T=6 K. Bunching of the basal plane moments around the easy hexagonal direction has been observed below T=50 K. Evidence for asphericity in the magnetization density is presented and discussed. The wave vector of the basal plane modulation decreases monotonically with temperature in general accordance with the Elliott–Wedgewood theory. Several inflection points were observed, however, which correspond to commens...
TL;DR: In this paper, the magnetic noises in rapidly quenched amorphous magnetic materials were examined, and the following results have been obtained: 1) CoFeSiB materials show the lowest noise, 2) Water quenching treatment decreased the noise remarkably, 3) The lower Curie temperature leads to the lower magnetic noise, and 4) Some Co base amorphus have the performance comparable to or better than that of the conventional polycrystalline material such as Supermalloy.
Abstract: Magnetic noises in rapidly quenched amorphous magnetic materials were examined. Magnetic noises are observed as the fluctuations of the induced voltage wave forms of the magnetic cores on every cycle of the alternating exciting field. Fe, Ni, and Co base alloys were tested, and the following results have been obtained. 1) CoFeSiB amorphous materials show the lowest noise, 2) Water quenching treatment decreased the noise remarkably, 3) The lower Curie temperature leads to the lower magnetic noise. 4) Some Co base amorphous alloys have the performance comparable to or better than that of the conventional polycrystalline material such as Supermalloy.
TL;DR: In this paper, low-temperature specific heat, electrical resistivity, ac magnetic susceptibility, and dc magnetization measurements were made on ternary cerium and uranium transition metal borides with the general formula CeT3B2 (T=Co, Ru, Rh, and Ir) and UT3B 2 (T = Co, Ru and Ir).
Abstract: Low-temperature specific heat, electrical resistivity, ac magnetic susceptibility, and dc magnetization measurements were made on ternary cerium and uranium transition metal borides with the general formula CeT3B2 (T=Co, Ru, Rh, and Ir) and UT3B2 (T=Co, Ru, and Ir). The compound CeRu3B2 was found to exhibit superconductivity below 0.68 K. The values of the electronic specific heat coefficient range from 9.7 mJ/mole-K2 for CeCo3B2 to 64 mJ/mole-K2 for UIr3B2. The electrical resistivity versus temperature curves of all of the compounds exhibit negative curvature and are reminiscent of valence fluctuation behavior. In the case of CeIr3B2, the electrical resistivity attains a maximum value at 180 K, while the dc magnetic susceptibility has a temperature dependence that is typical of intermediate valence Ce compounds, approaching a finite value at zero temperature. The electrical resistivity of the ferromagnetic compound CeRh3B2 reveals a rapid decrease in spin disorder resistivity below 120 K. The dc magnetic susceptibility of this material can be described as the sum of a constant term and a Curie-Weiss contribution with an effective magnetic moment of 1.01 µB per formula unit and a Curie-Weiss temperature of 119 K. Magnetization measurements on CeRh3B2 yield a saturation magnetic moment of 0.37 µB per formula unit and a Curie temperature of 113 K.
TL;DR: Inelastic neutron scattering measurements have been performed on a Ni0.784Mn0.216 disordered alloy which is ferromagnetic below 330K as discussed by the authors, and the inelastic scattering reveals a marked anomaly of the spin dynamics at about 100k below which a quasi-elastic line appears and grows in intensity as commonly observed in similar reentrant systems.
Abstract: Inelastic neutron scattering measurements have been performed on a Ni0.784Mn0.216 disordered alloy which is ferromagnetic below 330K. At temperatures lower than 40K the AC susceptibility measurements suggest the onset of a frustrated phase. Spin waves have been unambiguously observed at all temperatures below the Curie temperature 330K, and in particular below 40K. The inelastic scattering reveals a marked anomaly of the spin dynamics at about 100K below which a quasi-elastic line appears and grows in intensity as commonly observed in similar re-entrant systems. This anomaly is characterised by a large enhancement of the spin-wave damping, a marked change of the transverse static susceptibility which is higher in the 'spin-glass phase' than in the ferromagnetic phase and, at lower temperatures (below 70K), an increase of the stiffness constant. These experimental results are in contradiction with models suggesting a simple break-up of the infinite ferromagnetic network established at TC.