The nature of the magnetism in quasi-2D layered α-Ni(OH)₂

Abstract

The two layered hexagonal hydroxides of Ni are β-Ni(OH)(2) and α-Ni(OH)(2); β-Ni(OH)(2) is now known to be an antiferromagnet whereas the nature of the magnetism in α-Ni(OH)(2) is not yet well established. Here, the magnetic properties of α-Ni(OH)(2) with lattice parameters a = 3.02 Å and c = 8.6 Å, and flower-like morphology with petal thickness of approximately equal to 50 Å are reported. Temperature (2-300 K) and magnetic field (up to 65 kOe) dependence of the magnetization and ac susceptibility at f = 0.1-1000 Hz were measured. Analysis of the data yields ferromagnetic ordering in the system with T(C) is approximately equal to 16 K. In addition, a nanosize related blocking temperature T(B) = 8 K and spin-glass-like ordering of the surface spins near 3.5 K are inferred from the ac frequency and dc magnetic field dependence of these transitions. Fitting to the high temperature series and quasi-2D nature of the system is used to determine J(1)/k(B) = 4.38 K (J(2)/k(B) = 0.14 K) for the intraplane (interplane) exchange coupling between the Ni(2+) ions.

Hybrid interfaces in layered hydroxides: magnetic and multifunctional superstructures by design

“…These compounds are ferromagnetic in keeping with recent reports on α-Ni(OH)2 analogues [105,106]. This behavior has been discussed on the basis of the Drillon-Panissodmodel for the magnetic layers interacting via dipolar interactions [100] and taking into account the structural features determined by XANES and XRD, as well as the intrinsic properties of the halide ion.…”

Nickel hydroxides and related materials: a review of their structures, synthesis and properties

“…In contrast to β-Ni(OH) 2 (referred to simply as Ni(OH) 2 in many of the early papers), very little research has been carried out into the magnetic properties of α-Ni(OH) 2 . We know of only the study by Rall et al [217,218] on α-Ni(OH) 2 • 3.3H 2 O in the form of flowers with a petal thickness of approximately 5 nm and with lattice constants of a = 3.0 Å and c = 8.6 Å. Comparative studies of the magnetic susceptibility of powdered samples of α-Ni(OH) 2 and β-Ni(OH) 2 yielded maxima at 13-16 K and 25 K, respectively, and a 40 times greater value for the field-cooled susceptibility in α-Ni(OH) 2 versus that in β-Ni(OH) 2 , indicating differences in their magnetic ordering.…”

Nature of magnetic interactions in β-Co(OH)2 nanoparticles

“…Transition metal hydroxides are known to exhibit unusual and interesting magnetic behavior . These materials also have many technological applications .…”