Metamagnetism

About: Metamagnetism is a research topic. Over the lifetime, 2023 publications have been published within this topic receiving 38108 citations.

First-order metamagnetic transition in iron monosilicide

Abstract: The influence of a high magnetic field on the band structure and optical conductivity of FeSi has been studied by the ab initio full-potential LMTO-PW and relativistic LMTO-ASA methods with an applied field included. It is found that the applied external magnetic field induces a metallic magnetic state through a first-order metamagnetic transition, i.e. at a critical magnetic field of about there is a large steplike increase in the calculated magnetization, with a magnetic moment of . The magnetized state persists while the field is gradually reduced from above the metamagnetic transition (a hysteresis effect). The calculated optical conductivity (OC) at the critical field differs substantially from the zero-field OC in the infrared region.

Metamagnetic transition and magnetic properties of UPt3.

Abstract: We report fully relativistic band structure and total energy studies of ${\mathrm{UPt}}_{3}$ in the different magnetic states. We find that the ground state of ${\mathrm{Upt}}_{3}$ is nonmagentic, even though stable ferromagnetic and antiferromagnetic solutions are also found. We find that the total energy calculations predict the direction of the ordered moment correctly and for the first time the ``metamagnetic transition'' is found from a first principles total energy calculation for heavy fermion compounds.

Local-Ising type magnetic order and metamagnetism in the rare-earth pyrogermanate Er$_2$Ge$_2$O$_7$

Abstract: The recent discoveries of proximate quantum spin-liquid compounds and their potential application in quantum computing informs the search for new candidate materials for quantum spin-ice and spin-liquid physics. While the majority of such work has centered on members of the pyrochlore family due to their inherently frustrated linked tetrahedral structure, the rare-earth pyrogermanates also show promise for possible frustrated magnetic behavior. With the familiar stoichiometry $RE_2$Ge$_2$O$_7$, these compounds generally have tetragonal symmetry with a rare-earth sublattice built of a spiral of alternating edge and corner sharing rare-earth site triangles. Studies on Dy$_2$Ge$_2$O$_7$ and Ho$_2$Ge$_2$O$_7$ have shown tunable low temperature antiferromagnetic order, a high frustration index and spin-ice like dynamics. Here we use neutron diffraction to study magnetic order in Er$_2$Ge$_2$O$_7$ (space group $P4_{1}2_{1}2$ ) and find the lowest yet Neel temperature in the pyrogermanates of 1.15 K. Using neutron powder diffraction we find the magnetic structure to order with $k = (0,0,0)$ ordering vector, magnetic space group symmetry $P4_{1}^{'}2_{1}2^{'}$ and a refined Er moment of $m = 8.1 \mu_B$ - near the expected value for the Er$^{3+}$ free ion. Provocatively, the magnetic structure exhibits similar 'local-Ising' behavior to that seen in the pyrocholres where the Er moment points up or down along the short Er-Er bond. Upon applying a magnetic field we find a first order metamagnetic transition at $\sim$ 0.35 T to a lower symmetry $P2_{1}^{'}2_{1}^{'}2$ structure. This magnetic transition involves an inversion of Er moments aligned antiparallel to the applied field describing a class I spin-flip type transition, indicating a strong local anisotropy at the Er site - reminiscent of that seen in the spin-ice pyrochlores.

High field transitions in (Fe, T)3Ga4 alloys

Abstract: Magnetization of a series of transition metal alloys (Fe1−xTx)3Ga4 with T = Mn, V, Cr and Ti having values of x in the range 0.05 ⩽ x ⩽ 0.2 has been examined as a function of the magnetic field (0–12 T) and temperature (4–300 K). The alloys have the same base-centred monoclinic crystal structure as Fe3Ga4 and, in general, show a low field metamagnetic transition similar to that seen for Fe3Ga4. In the low temperature regime, many of the alloys also show an apparent first order transition at much higher fields (∼ 6 T) to a ferromagnetic state. The large hysteresis associated with this transition may indicate a magnetostrictive origin. Preliminary neutron diffraction results obtained at ISIS indicate that a small lattice contraction occurs in transforming to the antiferromagnetic state. The magnetic phase diagrams are interpreted in terms of theoretical results by Moriya and Usami [Solid State Commun. 23 (1977) 935] and Isoda [J. Phys. Soc. Japan 53 (1984) 3587] on magnetic phase transitions in itinerant electron systems.