EPR-Determined Anisotropy of the g-Factor and Magnetostriction of a Cu2MnBO5 Single Crystal with a Ludwigite Structure

Dubrovskiy, A. A.; Rautskii, M. V.; Moshkina, E. M.; Yatsyk, I. V.; Eremina, R. M. JETP LETTERS, 106 (11):716-719; 10.1134/S0021364017230072 DEC 2017

Electron paramagnetic resonance (EPR) and magnetostriction of the Cu2MnBO5 single crystal have been studied. The EPR spectrum consists of a single Lorentzian line due to the exchange-coupled system of spins of Cu2+ and Mn3+ ions. It has been established experimentally that the g-factor in the paramagnetic region is strongly anisotropic and anomalously small, which is not typical of the exchange-coupled system of spins of Cu2+ and Mn3+ ions. At a temperature of 150 K, the g-factors along the crystallographic a, b, and c axes are 2.04, 1.96, and 1.87, respectively. Such small effective g-factor values can be due to the effect of the anisotropic Dzyaloshinskii–Moriya exchange interaction between the spins of Cu2+ and Mn3+ ions directed along the a axis. The presence of two Cu2+ and Mn3+ Jahn–Teller ions occupying four nonequivalent positions in the crystal is responsible for the absence of the inversion center. It is found that the behavior of the magnetostriction of Cu2MnBO5 is not typical of transition-metal crystals but is closer to the behavior of crystals containing rare-earth ions.