Resonance Observation of Antiferromagnetic Ordering in RbMnCl3, CsMnCl3, and KMnCl3

• Published in: Journal of applied physics 1965-03, Vol.36 (3), p.1195-1196
• Main Authors: Kedzie, R. W., Shane, J. R., Kestigian, M., Croft, W. J.
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.1714166

Paramagnetic and antiferromagnetic resonances have been observed as a function of temperature in KMnCl3, CsMnCl3, and RbMnCl3 at 9.5 Gc/sec (X band) and 25 Gc/sec (K band). The linewidth (ΔH) of the nearly cubic KMnCl3 [ΔH (298°K) = 24 G] remains constant in the paramagnetic region. The ordering temperature (TN = 100±3°K) is sharply defined by resonance measurements. At T = TN the K-band PMR abruptly and simultaneously broadens and splits into four anisotropic components. The AFMR lines move rapidly to zero applied magnetic field and then back up to 10.5 kG as the temperature is lowered. In contrast, the PMR linewidth of CsMnCl3 [ΔH (297°K) = 40 G] does not remain constant but rises rapidly from 62 G at 100°K to 240 G at 77°K (TN = 69°±3°K). AFMR is observed below the ordering temperature and, as the temperature decreases, the linewidth decreases to 36 G at 5°K. The origin of an additional resonance in the g = 2 region which is observed down to a temperature of 35°K is discussed. RbMnCl3 has a room-temperature linewidth of 39 G which increases slowly to 60 G at 107°K and then rapidly to more than 155 G at 95°K suggesting an antiferromagnetic transition with TN = 86°±6°K. The resonances observed at X and K band below the ordering temperature are described.