Magneto-optical microwave spectroscopy of the coherent magnetic state in the mixed valance compound SmBe in the frequency range 40-120 GHz
Demishev S.V., Semeno A.V., Sluchanko N.E., Samarin N.A., Singleton J., Ardavan A., Blundell S.J., Hayes W., Kunii S.
![<b>In undoped pure single crystals of the mixed valance compound SmBe anomalous ESR absorption has been observed in the frequency range <i>ν ~ </i>40 — 120 GHz at temperatures of 1.8 — 4.2 K. The ESR for the case of the coherent ground state consists of two components corresponding to g-factors <i>g\ ~ </i>1.9O7±O.O03 and <i>дг — </i>1.890±0.003. The amplitude of both ESR lines strongly depends on temperature in the temperature range studied: the amplitude of the first line with <i>g " g\ </i>increases and the amplitude of the second line decreases with temperature. A model based on consideration of the intrinsic defects in the SmBe crystalline lattice having concentration ~ 10'<sup>5</sup> — 10'* cm<sup>-3</sup> is suggested for the explanation of the anomalous ESR-behaviour. In the frequency range <i>ν </i>>70 GHz at Τ 4.2 К, in addition to the main ESR lines, a new magnetic resonance with an hysteresis-like field dependence is discovered.</b> <b>PACS: </b><a href="http://75.30.-m"><b>75.30.-m</b></a>](/ps/985/article_15003_800_head.png)
In undoped pure single crystals of the mixed valance compound SmBe anomalous ESR absorption has been observed in the frequency range ν ~ 40 — 120 GHz at temperatures of 1.8 — 4.2 K. The ESR for the case of the coherent ground state consists of two components corresponding to g-factors g\ ~ 1.9O7±O.O03 and дг — 1.890±0.003. The amplitude of both ESR lines strongly depends on temperature in the temperature range studied: the amplitude of the first line with g " g\ increases and the amplitude of the second line decreases with temperature. A model based on consideration of the intrinsic defects in the SmBe crystalline lattice having concentration ~ 10'5 — 10'* cm-3 is suggested for the explanation of the anomalous ESR-behaviour. In the frequency range ν >70 GHz at Τ 4.2 К, in addition to the main ESR lines, a new magnetic resonance with an hysteresis-like field dependence is discovered. PACS: 75.30.-m