Electron magnetic resonance of iron-gallium borate single crystals

Abstract

Electron magnetic resonance (EMR) studies of iron gallium borate, Fe x Ga 1−x BO 3 , single crystals have been carried out in the frequency range ca. 8 38 GHz in magnetizing fields up to 10 kOe and the temperature range of 4 310 K. With decreasing x in the range of 0:34 x 1, the EMR spectra show a gradual passage from a low frequency antiferromagnetic resonance (AFMR) mode at x = 1 toward a coexistence of AFMR and cluster magnetic resonance arising, respectively, from completely and partially magnetically ordered crystal regions. Temperature and concentration dependences of magnetic characteristics of iron gallium borates, namely, the Néel temperature, the Dzyaloshinskii Moriya field, and the isotropic energy gap, have been determined by means of AFMR. In contrast to unmixed FeBO 3 , Fe x Ga 1−x BO 3 crystals with 0:34 x 0:85 show anomalous nonmonotonic temperature dependences of the Dzyaloshinskii Moriya field with a maximum well below the Néel temperature suggesting the occurrence of another magnetic transition in this temperature range.

Flux growth, structure refinement and Mössbauer studies of Fe1– x Ga x BO3 single crystals

“…9(b)]. This result correlates well with the values of Né el temperatures obtained by antiferromagnetic resonance for Fe 1-x Ga x BO 3 single crystals (Seleznyova et al, 2019).…”

“…Isomorphous substitution of paramagnetic Fe 3+ by diamagnetic Ga 3+ leads to a decrease in the Dzyaloshinskii-Moriya and magnetocrystalline anisotropy fields, and also the Né el temperature (Yagupov et al., 2015;Seleznyova et al, 2019); Mogilenec et al, 2019). By diamagnetic dilution of the iron substructure by gallium ions, crystals in the Fe 1-x Ga x BO 3 ISSN 2052-5206 # 2020 International Union of Crystallography solid solution system with desired properties can be synthesized.…”