Coupling of ferroelasticity and ferromagnetism in La1-xSrxCoO3 twin crystals

In the present study, x-ray diffraction experiments under magnetic fields were carried out for La0.57Sr0.44CoO3.01 twin crystals with a trigonal structure by Laue method in addition to magnetization measurements. Crystallographic domains (variants) in a ferromagnetic phase of the crystals were rearranged by applying magnetic fields and the rearranged structure remained even after the applied magnetic fields were changed to zero, indicating a coupling of ferroelasticity and ferromagnetism. The present results were consistently understood by the large uniaxial magnetocrystalline anisotropy with an easy plane of magnetization parallel to the hexagonal ab plane of the trigonal structure. The origin of the large magnetocrystalline anisotropy was discussed in relation to the spin states of Co ions.