Magnetic properties of Bi-doped

Electron Spin Resonance Study of Polycrystalline La0.4Bi0.1Ca0.5MnO3

“…1. The results agree with those found previously [3]. First, one can observe that our sample is characterized by the presence of several magnetic transitions.…”

“…It is obvious that T C value is about 225 K. The magnetic transition recorded at 50 K can be attributed to a spinglass like state. In fact, all the bismuth substituted samples La 0.5−x Bi x Ca 0.5 MnO 3 were characterized by such state at low temperature [3]. Besides, for x = 1/16 and x = 1/8, the authors have noticed the presence of CO transition between 200 and 225 K [3].…”

“…On cooling, this compound undergoes from paramagnetic (PM) to ferromagnetic (FM) state at T C = 220 K and then from FM to charge ordered antiferromagnetic (CO-AFM) state at T CO = 150 K with a CE-type CO [6]. La 3+ and Bi 3+ ions practically have the same ionic radius value [7], so we can expect that Bi 0.5 Ca 0.5 MnO 3 will evolve like La 0.5 Ca 0.5 MnO 3 However, experiments have shown that Bi 0.5 Ca 0.5 MnO 3 undergoes while cooling from PM to CO state at T CO = 325 K, and this transition is followed by another one to AFM state at T N = 120 K with the existence of a spinglass like state under 50 K [3]. Besides, Bi 0.5 Ca 0.5 MnO 3 has a C-type AFM structure below T N [5].…”

“….) are very interesting compounds, and they are the subject of several investigations, not only for their technological applications, but also for the complexity of behavior and the diversity of physical phenomena existing in such samples [1][2][3][4][5]. Generally, halfdoped manganites are characterized by charge ordering (CO) phenomenon which consists in having a real space ordering of Mn 4+ and Mn 3+ ions.…”

“…Besides, Bi 0.5 Ca 0.5 MnO 3 has a C-type AFM structure below T N [5]. Previously, Li et al have studied the electrical and magnetic properties of La 0.5−x Bi x Ca 0.5 MnO 3 system [3,4]. However, we have noticed some anomalies in electron spin resonance (ESR) spectra, especially for the compound with x = 1/16: even the sample is PM above 250 K, the ESR signal is not symmetrical for the temperature values 260 and 265 K [3].…”