2004/08/09 by A. P. Litvinchuk, M. N. Iliev, M. Pissas +1
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Rare-earth and actinide compounds #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1016/j.ssc.2004.08.006
published as Solid State Commun. 132, 309 (2004) · 4 pages, 5 figures
arxiv created 2004/08/09 · openalex publication_date 2004/08/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report an infrared reflection spectroscopy study of La1/2Ca1/2MnO3 over a broad frequency range and temperature interval which covers the transitions from the high temperature paramagnetic to ferromagnetic and, upon further cooling, to antiferromagnetic phase. The structural phase transition, accompanied by a ferromagnetic ordering at TC=234 K, leads to enrichment of the phonon spectrum. A charge ordered antiferromagnetic insulating ground state develops below the Néel transition temperature TN=163 K. This is evidenced by the formation of charge density waves and opening of a gap with the magnitude of 2Δ0 = (320 ± 15) cm-1 in the excitation spectrum. Several of the infrared active phonons are found to exhibit anomalous frequency softening. The experimental data suggest coexistence of ferromagnetic and antiferromangetic phases at low temperatures.