• S V Petrov

Articles written in Pramana – Journal of Physics

• Magnetic properties and peculiarity of magnetic states in dilute antiferromagnets Mn1−xZnxF2

The dependence of magnetic moment and susceptibility on temperature, magnetic field and frequency of some single crystals Mn1−xZnxF2 (xxe=0.75—percolation limit) were experimentally investigated. Our experiments show that (Bazhan and Petrov 1984; Cowleyet al 1984; Villain 1984) in these crystals the nonequilibrium magnetic state of spinglass type with finite correlation length appears as temperature decreasesT&lt;T in weak magnetic fields. This state is determined by fluctuation magnetic moments √ (wheren is the number of magnetic ions, corresponding to finite correlation length andμ the magnetic moment Mn+1).

In the experiments in low magnetic fields and frequencies there are no peculiarities in the magnetic susceptibility temperature dependence atTTf. At temperaturesT&gt;Tf andT&lt;Tf magnetic susceptibility is determined by$$\chi \left( {T &gt; T_f } \right) = \frac{{N\left\langle \mu \right\rangle ^2 }}{{3k\left( {T + \theta } \right)}} = \frac{N}{n}\frac{{\left\langle {\sqrt n \mu } \right\rangle ^2 }}{{3k\left( {T + \theta } \right)}} = \chi \left( {T&lt; T_f } \right)$$. In strong magnetic fields and large frequencies there are peculiarities in thex(T) dependence atT=Tf. AtT&lt;Tf and strong magnetic fieldsX(T)=x0 andT&lt;Tf and at large frequenciesx(T)=x0+α/T.

The dependences of magnetic susceptibility on the frequency are determined by the magnetic system relaxation. Calculations and comparison with experiments show that the relaxation of the investigated magnetic systems atT&lt;Tf follows the relaxation lawM(t)=M(0) exp[−(t/τ)r], suggested in Palmeret al (1984) for spin-glasses relaxation taking into account the time relaxation distributionτ0....τmax in the system and its ‘hierarchically’ dynamics.

• # Pramana – Journal of Physics

Volume 96, 2022
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019