Magnetoelectric effect of Cr₂O₃in strong static magnetic fields

Unexpectedly Large Electronic Contribution to Linear Magnetoelectricity

“…This analysis shows that α el contributes one fourth of the total spin-driven magnetoelectric response of Cr 2 O 3 . The total response that we compute is in good agreement with zero-temperature extrapolations of experimental measurements, which range [7,20,21] from 2-4.7 × 10 −4 emu-CGS. Off-diagonal ME response of LiNiPO 4 : The lithium orthophosphates LiMPO 4 (M=transition metals) are currently attracting much interest for their potential use as cathodes in Li-ion batteries, as well as for their large magnetoelectric responses and the recent observation of ferrotoroidic domains in LiCoPO 4 [22].…”

Hidden orbital polarization in diamond, silicon, germanium, gallium arsenide and layered materials

“…Additionally, the induced magnetization at each site of silicon can be larger than the total induced magnetization of Cr 2 O 3 , the most well-known magnetoelectric material, with a m 0 dM=dε value of approximately 1 ps m − 1 . 29 Again, we are not claiming that compressed silicon is the best material for antiferromagnetic information technology exploiting the hidden orbital polarization; larger current-induced antiferromagnetism is expected in lower-symmetry materials. However, our proof-ofconcept calculations illustrate that it is a worthwhile research direction to search for materials with large hidden orbital polarizations useful in antiferromagnetic information technology, irrespective of the size of the SOC.…”

Magnetoelectric Cr2O3 and relativity theory

“…In the constant case, the α jumps at the interface between the medium and vacuum and yields a contribution to the corresponding boundary conditions, see [41]. Moreover, at least since the very exact measurements of Wiegelmann et al [68] no doubt was possible at the violation of the Post constraint in the case of the antiferromagnet Cr 2 O 3 .…”

“…Further experiments were then done mainly for the ME H case. Particular accurate measurements are those of Wiegelmann et al [68], see also [67,69]. They took magnetic fields B as high as 20 tesla and measured from liquid Helium up to room temperature.…”

“…Wiegelmann et al took a quasi-static magnetic field and thereby proved explicitly that measurements with magnetic fields of some kilo hertz can be extrapolated to static measurements. The sign of α ⊥ (T ) relative to α || (T ) was left open in [68]. Hence we took that from Astrov [4].…”