Magnon contribution to the magnetic specific heat of the spin-glass Cd0.5Mn0.5Te: 0.5 K≤T≤4.5 K

Abstract

We calculate the magnon contribution to the magnetic specific heat of the spin-glass ${\mathrm{Cd}}_{0.5}$ ${\mathrm{Mn}}_{0.5}$Te. Good agreement is obtained with the measured values in the interval $0.5\le T\le 4.5$ K with the interactions $J_{\mathrm{NN}}=10\mathrm{}{J}_{\mathrm{NNN}}=-12\mathrm{}$ K and an anisotropy gap $\approx 2-4$ K. The theoretical results are obtained from a numerical calculation of the energies of the magnon modes in finite arrays of spins with ground-state configurations found by minimizing the energy of the corresponding classical Heisenberg Hamiltonian. The values chosen for the exchange integrals also account for the inelastic neutron scattering at $Q=(1,0,0)\mathrm{}$, $T=1.8\mathrm{}$ K.