NMR study of successive magnetic transitions in the A-site ordered perovskite LaMn3Cr4O12

作者：Kawasaki Yu^*; Takase Syota; Kishimoto Yutaka; Ohno Takashi; Yamada Ikuya; Shiro Kentaro; Takahashi Ryoji; Ohgushi Kenya; Nishiyama Norimasa; Inoue Toru; Irifune Tetsuo

来源：Journal of the Korean Physical Society, 2013, 63(3): 640-643.

DOI：10.3938/jkps.63.640

• Perovskite antiferromagnet
• Magnetic structure
• Nuclear magnetic resonance

We have investigated the successive magnetic phase transitions of the A-site ordered perovskite LaMn3Cr4O12 by measuring La-139 nuclear magnetic resonance (NMR) spectra. The successive magnetic transitions are revealed by a very small but clear increase in the full width at half maximum (FWHM) of the La-139 NMR signal at T (M2) = 150 K and by the disappearance of the signal due to the line broadening at temperatures below T (M1) = 50 K. These two magnetic transitions are associated with independent orderings within the Cr-site sublattice at T (M2) and within the Mn-site sublattice at T (M1). Regarding the magnetic structure of the Cr-site sublattice at temperatures below T (M2), the cancellation of internal fields at the La site, ruling out ferromagnetic and multi-q antiferromagnetic structures, is consistent with the typical antiferromagnetic structure for perovskites, such as G-, A- and C-type orders. The uncanceled internal field at the La site at temperatures below T (M1) is also consistent with these typical antiferromagnetic structures in the Mn-site sublattice. The differences in the temperature dependences of the Knight shift K(T) and the bulk susceptibility chi(T) are consistently explained by the independent magnetic orderings of the Cr- and the Mn-site sublattices and the cancellation of internal field originating from the Cr-site sublattice at the La site at temperatures below T (M2).

• 出版日期2013-8