Magneto-optical study of holmium iron garnet Ho3Fe5O12
A.M. Kalashnikova1, V.V. Pavlov1, A.V. Kimel2, A. Kirilyuk2, Th. Rasing2, and R.V. Pisarev1
1A.F. Ioffe Physico-Technical Institute, 26 Politekhnicheskaya Str., St. Petersburg 194021, Russia
2Radboud University Nijmegen, Institute for Molecules and Materials, Nijmegen 6525AJ, The Netherlands pos Анотація:
Received May 10, 2012
Bulk holmium iron garnet Ho3Fe5O12 is a cubic ferrimagnet with Curie temperature TC = 567 K and magnetization compensation point between 130–140 K. The magneto-optical data are presented for a holmium iron garnet Ho3Fe5O12 epitaxial ~10 μm thick film grown on a (111)-type gadolinium-gallium garnet Gd3Ga5O12 substrate. A specific feature of this structure is the closeness of the parameters of the bulk material, from which the film has been grown, to the substrate ones. Temperature and field dependences of the Faraday effect and temperature dependence of the domain
structure in zero field are investigated. The compensation point of the structure is found to be Tcomp = 127 K. It is shown that the temperature dependence
of characteristic size of the domain structure diverges at this point. It is established that the magnetic anisotropy
of the material is determined by both uniaxial and cubic contributions, each being characterized by different temperature dependence. A complex form of hysteresis loops and a sharp changes of the domain pattern with varying temperature suggest that there occur
collinear–noncollinear phase transitions. Study of the optical second harmonic generation was carried
out using 100 fs laser pulses with central photon energy E = 1,55 eV. The electric dipole contribution (both crystallographic and magnetic) to the second harmonic generation was observed with high reliability despite a
small mismatch of the film and substrate parameters.
PACS: 75.50.Gg Ferrimagnetics; PACS: 78.20.–e Optical properties of bulk materials and thin films; PACS: 42.65.Ky Frequency conversion; harmonicgeneration, including higher-order harmonic generation.
Key words: holmium iron garnet, ferrimagnets, epitaxial films, magneto-optical research.