Study of the crystal electric field interaction in single crystals

Abstract

Magnetization measurements along the main symmetry directions of the tetragonal structure, [100], [110] and [001], have been performed on several single crystals (R = Y, Tb and Ho), at applied high magnetic fields up to 12 Tesla and temperatures ranging from 4.2 to 300 K. From the measurements on the yttrium compound the second- and fourth-order anisotropy constants and the spontaneous magnetization of the Fe sublattice have been determined. The complex magnetic behaviour has been explained using a single-ion model for the crystal electric field (CEF) interaction and a mean-field model for the exchange interaction. A reliable set of CEF parameters and mean exchange field have been obtained for the and intermetallic compounds. All the experimental features observed, the first-order magnetization process under magnetic field in and spin reorientation transition (SRT) in , have been explained using such CEF and exchange parameters. A study of the character of the SRT observed in the intermetallic compound has been undertaken by measuring the parallel and perpendicular components of the magnetization to the applied magnetic field. The experimental results obtained have been explained considering the coexistence of two magnetic phases for temperatures close to the spin reorientation one.

Noncollinearity of the magnetic structure of TbFe10V2

“…The crystal-field parameters deduced for the TbFe 10 Si 2 are inapplicable to TbFe 10 V 2 since Si, unlike either V or Ti, shows preferential occupation of the 8 f and 8 j sites, rather than the usual 8i site preference, with a concomitant effect on the Tb 3ϩ crystal field. Abadia et al 9 determined crystal-field parameters for TbFe 11 Ti from single-crystal measurements but these are inapplicable to TbFe 10 V 2 since the EMD of TbFe 11 Ti is along ͓100͔ over the entire temperature range 4 -300 K, whereas TbFe 10 V 2 has easy ͓001͔ in the range TϾ170 K and only cants towards the ͑001͒ plane as T→0 K.…”

Influence of low Co substitution on magnetoelastic properties of HoFe11Ti intermetallic compound

“…Pseudo-ternary compounds of the type RFe 11 À x Co x Ti also crystallise in the ThMn 12 structure [4]. In the past two decades, magnetic properties and magnetic structure of RFe 11 Ti have been studied in order to investigate the nature of the field-induced magnetic phase transitions [5][6][7]. Many researches have also been performed on the investigation of magnetoelastic properties of intermetallic compounds based on RFe 12 À x M x [8][9][10][11][12].…”

Magnetic microstructure of YFe11Ti aggregates

“…[3][4][5][6][7]). In these fundamental studies, compounds with non-magnetic R, such as YFe 11 Ti, which exhibit c as the easy magnetization axis due to the Fe sub-lattice, have been used to deduce the R-Fe exchange for the rest of the compounds [8]; propose crystal-field models for the 4f sub-lattice [8][9][10][11]; and analyze thermal expansion anomalies [10] and spontaneous magnetostriction [10] in the series. Diffraction studies have been used to refine the structure and determine the lattice parameters of the tetragonal YFe 11 Ti phase (a = 0.851 nm and c = 0.480 nm [10,12]).…”