Showing papers on "Spin canting published in 1990"
TL;DR: In this article, the spin-canting anomaly was investigated by high-field Mossbauer spectroscopy and it was shown that the likely presence of antiferromagnetic impurities greatly confounded the interpretation of earlier experiments.
Abstract: The spin-canting anomaly, in which fine ferrimagnetic iron oxide particles are not completely saturated by very large applied magnetic fields, is investigated by high-field Mossbauer spectroscopy. Until now it has been thought that randomly oriented moments near surfaces were responsible. High-quality data are used to repudiate this view. Ferric ions on A sites are collinear with the applied field, whereas those on B sites are not quite collinear. Further, it is shown that the likely presence of antiferromagnetic impurities greatly confounds the interpretation of earlier experiments.
22 citations
TL;DR: In this paper, the antiferromagnetic spin arrangement in all the compounds is consistent with the chemical unit cell of the tilt system of MnCl6 octahedra, alternately rotating about the b axis.
Abstract: Weak ferromagnetism in the layered perovskite (C n H2n+1NH3)2MnCl4((n = 1, 2 and 3) has been studied by means of neutron diffraction and SQUID magnetometry. The antiferromagnetic spin arrangement in all the compounds is consistent with the chemical unit cell of the tilt system of MnCl6 octahedra, alternately rotating about the b axis. The weak ferromagnetic moment due to spin canting in the direction of the a axis of the compound with n = 3 is 0.42 × 10−3 μB at 4.2 K; the spin canting can be ascribed to an antisymmetric exchange interaction through a coupling of the spin directions and the tilting directions of the MnCl6 octahedra. The critical index β of the antiferromagnetic moment and that of the weak ferromagnetic moment for this compound are 0.25 + 0.02 and 0.229 + 0.005, respectively; the results reflect the character of the two-dimensional magnetic system. For the compounds with n = 1 and 2 the weak ferromagnetic moments are found in the c-plane.
18 citations
TL;DR: In this paper, anomalous decreases in hopping electron activation energies are discussed on the basis of breakdown in antiferromagnetic ordering through spin canting of the Ni sublattices through exchange isolation caused by diamagnetic Li1+ ions that group with the low-spin Ni3+ (S= (1)/(2) ) to form polarons, and enhanced disruption of magnetic superexchange that results from a combination of Li 1+ dilutants and S=0 states of surrounding Ni2+ ions induced at low temperatures by static Jahn-Teller tetr
Abstract: Magnetic and electronic properties of the mixed‐valence semiconductor LixNi2+1−2xNi3+xO are reinterpreted in terms of low‐spin states for both Ni ions. Anomalous decreases in hopping electron activation energies are discussed on the basis of (i) breakdown in antiferromagnetic ordering through spin canting of the Ni sublattices through exchange isolation caused by diamagnetic Li1+ ions that group with the low‐spin Ni3+ (S= (1)/(2) ) to form polarons, and (ii) enhanced disruption of magnetic superexchange that results from a combination of Li1+ dilutants and S=0 states of surrounding Ni2+ ions induced at low temperatures by static Jahn‐Teller tetragonal distortions of the oxygen octahedra around the Ni3+ polarons. Reported magnetic ordering and conduction anomalies in La2−xSrxNiO4 are then compared to the behavior of Cu in LixCu1−xO, and in the high‐Tc superconducting La2−xSrxCuO4 system. Spontaneous conduction through molecular‐orbital states involving zero‐spin Ni and Cu ions is discussed, together with t...
13 citations
TL;DR: In this paper, a series of Nd2(Co1−xFex)14B compounds with x=0.001, 0.01,0.02,0.,05, 0.,10 between 4.2 and 77 K were studied and a fast increase of the canting angle between the magnetization and c axis upon Fe substitution was found.
Abstract: 59Co NMR was studied in a series of Nd2(Co1−xFex)14B compounds with x=0.001, 0.01, 0.02, 0.05, 0.10 between 4.2 and 77 K. A fast increase of the canting angle between the magnetization and c axis upon Fe substitution has been found. Nonregular local environment effects in the form of rapidly developing satellite structure with significant intensity have been observed and tentatively attributed to the Fe influence on the crystal field experienced by the Nd sublattice.
7 citations
TL;DR: In this article, the authors collected spectra for three members of the spinel system Mg1+tFe2(1−t)Ti 2 O4 at temperatures down to 1.6 K and decomposed in A- and B-site components, both having a broad distribution of hyperfine fields.
Abstract: Spectra for three members of the spinel system Mg1+t
Fe2(1−t)Ti
t
O4, witht=0.5, 0.6 and 0.7, all showing re-entrant spin-glass-like behavior, were collected at temperatures down to 1.6 K and decomposed in A- and B-site components, both having a broad distribution of hyperfine fields. The numerical results suggest a more pronounced spin canting on A sites as compared to B sites. From spectra recorded at 4.2 K in an applied field of 6 T, and analysed with a sum of two bi-dimensional distributions of hyperfine fields and canting angles, the existence of reversed A-site spins is evidenced. The number of such spins increases with increasing magnetic dilution.
3 citations
TL;DR: In this paper, the Mossbauer spectra of ordered ferrites Li0.5Fe2.5−xAlxO4∶Sn for 0.8
Abstract: The57Fe and119Sn Mossbauer spectra of ordered ferrites Li0.5Fe2.5−xAlxO4∶Sn for 0.8
2 citations
TL;DR: In this article, a comparison of three fit models for analysis of the zero field Mossbauer spectra below T 0 is presented, based on discrete and distributed static hyperfine fields and magnetic relaxation.
Abstract: Zr3FeH5.3 exhibits hydrogen-induced magnetism below an ordering temperatureT0=135 K. Comparison of three fit models for analysis of the zero field Mossbauer spectra belowT0 is presented. The models are based on discrete and distributed static hyperfine fields and magnetic relaxation. The response of Zr3FeH5.3 to an applied field of 6.9 T indicates that antiferromagnetic interactions are present with spin canting also possible.