2008/10/01 by R. N. Bhowmik, R.N. Bhowmik, Asok Poddar +6
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Magnetic Properties of Alloys #Magnetic and transport properties of perovskites and related materials #Materials Science (cond-mat.mtrl-sci) #Soft Condensed Matter (cond-mat.soft) #cond-mat.mtrl-sci #cond-mat.soft
paper · pdf · doi:10.48550/arxiv.0810.0090
11 figures
arxiv created 2008/10/01 · openalex publication_date 2008/10/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the ferromagnetism of La0.67Ca0.33MnO3 in bulk polycrystalline, nanocrystalline and amorphous phase. The structural change from crystalline phase to amorphous phase exhibited a systematic decrease of TC(paramagnetic to ferromagnetic transition temperature) and spontaneous magnetization (MS). The experimental results suggested few more features, e.g., appearance of large magnetic irreversibility in the temperature dependence of magnetization, lack of magnetic saturation at high magnetic field, blocking of magnetization below TB, and enhancement of coercivity. In addition, the magnetic phase transition near to TC has changed from first order character in bulk sample to second order character in nanocrystalline and amorphous samples. We understand the observed magnetic features as the effects of decreasing particle size and increasing magnetic (spin- lattice) disorder. We noted that magnetic dynamics of amorphous samples is distinctly different from the nanocrystalline samples. The ferromagnetism of amorphous samples are comparable with the properties of reported amorphous ferromagnetic nanoparticles. We also demonstrate the effect of disorder shell in controlling the dynamics of ferromagnetic cores.