Mitsuru Suda

Magnetic Properties of Hydroxy Ni-Mica Intercalation

The magnetic properties of hydroxy Ni-mica intercalation complexes in which Ni forms two-dimensional lattices between mica layers have been investigated. The concentration of Ni was varied up to 21 wt%. The magnetic moment per Ni was evaluated from the Curie constants to be between 2 and 3 µB (dependent on the Ni content). Paramagnetic Curie temperatures obtained by the temperature dependence of the initial susceptibility are about 7-13 K for all the samples, while an apparent ferromagnetism is defined only for a sample with 2.6 wt% Ni by Arrott plots. These magnetic properties were explained by the formation of a Ni triad in a two-dimensional lattice because of the chemical stability of [Ni3(OH)5H2O]+ as an intercalant, and by a coaguration of triads with increasing Ni content.

2-Dimensional magnetism of hydroxy Mn- and Fe-mica intercalations

Abstract The two dimensional magnetism in a triangular lattice of hydroxy Mn- and Fe-mica intercalations has been investigated. The Fe-mica intercalation containing more than 8 wt%Fe shows an XY type ferrimagnetism with the ordering temperature of about 10 K. It is revealed by Mossbauer spectroscopy that only Fe 3+ is responsible for the ferrimagnetic ordering in the Fe-mica intercalation, although Fe 2+ ions coexist. The Mn-mica intercalation is most likely a Heisenberg type magnet with a near neighbour antiferromagnetic interaction, and a magnetic ordering is not found at least down to 4.2K. The M(M = Mn, Fe, Co and Ni) dependence of the 2-dimensional magnetic properties of the M-mica intercalations is discussed.

Magnetic characteristics of 3d transition‐metal–mica intercalation compounds

The magnetic properties of the M‐mica intercalation compounds (M=Mn,Fe,Co, and Ni) in which M elements form a two‐dimensional lattice between mica layers have been investigated. The content of the intercalated M element, x, was varied up to about 22 wt. %, which is about 81% with respect to the upper limit of x. The ac susceptibility measurements revealed the magnetic ordering around 10 K for the Fe‐ (x≥8.0 wt. %), Co‐ (x≥7.4 wt. %), and Ni‐mica intercalation compounds, but did not for the Mn‐mica. These magnetic orders are considered to be the two‐dimensional ones, caused from the intralayer superexchange interaction between M2+ (and Fe3+) ions.

Magnetic properties of hydroxy Co-Mica intercalation

Abstract The magnetic properties of hydroxy Co-mica intercalation complexes in which Co forms a two-dimensional lattice between mica layers have been investigated. The concentration of Co was varied up to 22 wt%. Ferromagnetism with the easy axis of magnetization in the ab -plane (layer plane) appears above about 5 wt%. The Curie temperature shows only a slight increase from about 7 to 8 K with increasing x up to 22.4 wt%. The magnetic moment m at 4.2 K measured in magnetic fields up to 80 kOe is about 2.3μ B ( P eff = 3.8μ B ), while P eff at high temperatures obtained by the Curie constant is about 5.3μ B . These magnetic properties are explained by the features of Co 2+ ions surrounded by an octahedral crystal and by a formation of Co 2+ clusters in the 2-dimensional lattice between mica layers.