N. Mufti, A.A. Nugroho, G.R. Blake, T.T.M. Palstra
We have studied the magnetodieletric coupling of polycrystalline samples of the spinels MCr2O4 (M = Mn, Co and Ni). Dielectric anomalies are clearly observed at the onset of the magnetic spiral structure (Ts) and at the 'lock-in' transition (Tf) in MnCr 2O4 and CoCr2O4, and also at the onset of the canted structure (Ts) in NiCr2O4. The strength of the magnetodielectric coupling in this system can be explained by spin-orbit coupling. Moreover, the dielectric response in an applied magnetic field scales with the square of the magnetization for all three samples. Thus, the magnetodielectric coupling in this state appears to originate from the P2M2 term in the free energy. © 2010 IOP Publishing Ltd.
Solid State Chemistry Laboratory, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, 9747AG Groningen, Nijenborgh 4, Netherlands; Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Bandung 40132, Jl. Ganesha 10, Indonesia; Department of Physics, Universitas Negeri Malang, Malang 65145, Jl. Surabaya 6, India
