NMR Study on the Supertransferred Hyperfine Magnetic Field at 55Mn in Ferromagnetic Perovskites La(Co1-xMgx)0.5Mn0.5O3
NMR Study on the Supertransferred Hyperfine Magnetic Field at 55Mn in Ferromagnetic Perovskites La(Co1-xMgx)0.5Mn0.5O3
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铁磁钙钛矿La(Co1-xMgx)0.5Mn0.5O3中55Mn超转移超精细磁场的NMR研究
DOI：
10.1143/jpsj.64.1326
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
M. Mizoguchi
中科院分区：
文献类型：
--
作者：
N. Nishimori;K. Asai;M. Mizoguchi
研究了铁磁氧化物La（Co2 + 1-xMgx 2+）0.5Mn0.54 + O3（0≤ x ≤ 0.4）的磁性和55 Mn处的超精细磁场.相邻Mn 4+和Co2+离子间超交换作用的交换积分J为+15.3K。55 Mn NMR谱由多个等距离分离的峰组成，解释为每个峰都是与Mn 4+相关的信号，周围有特定数量的Co2+离子。在La（Ni 1-xMgx）0.5Mn0.5O3氧化物体系中，相邻Co2+离子在55 Mn处产生的超转移超精细磁场HSTHF为+5.0kOe，明显小于Ni 2+离子的超转移超精细磁场HSTHF（+6.3kOe）.另一方面，由Mn 4+的3d磁矩产生的超精细磁场（~ 296 kOe）在两个体系中几乎相同。讨论了J和HSTHF值与氧离子2 p σ轨道自旋密度的关系。
Magnetic properties and the hyperfine magnetic fields at 55 Mn in ferromagnetic oxides La(Co 2+ 1- x Mg x 2+ ) 0.5 Mn 0.5 4+ O 3 (0≤ x ≤0.4) are studied. The exchange integral, J , for the superexchange interaction between neighboring Mn 4+ and Co 2+ ions is found to be +15.3 K in magnitude. 55 Mn NMR spectra, composed of several equidistantly separated peaks, are interpreted as each peak being the signal associated with Mn 4+ surrounded by a specific number of Co 2+ ions. The supertransferred hyperfine magnetic field, H STHF , at 55 Mn from each neighboring Co 2+ ion is found to be +5.0 kOe, which is considerably smaller than that (+6.3 kOe) from Ni 2+ in a similar oxide system La(Ni 1- x Mg x ) 0.5 Mn 0.5 O 3 . On the other hand, the hyperfine magnetic field (-296 kOe) originating from 3 d magnetic moment of Mn 4+ is virtually the same in both systems. The values of J and H STHF are discussed in relation with the spin density in 2 p σ orbitals of the oxygen ions.