Magnetic memory in a ceramic YBCO superconductor composed of sub-micron-size grains

作者：Deguchi Hiroyuki^*; Ashida Takuya; Syudo Mitsuhiro; Mito Masaki; Takagi Seishi; Hagiwara Makoto; Koyama Kuniyuki

来源：Journal of the Korean Physical Society, 2013, 62(12): 1832-1835.

DOI：10.3938/jkps.62.1832

• Memory effect
• Ceramic YBCO
• Chiral glass
• Random Josephson-coupled networks

The ceramic YBa2Cu4O8 (YBCO) composed of sub-micron-size grains is considered as a random Josephson-coupled network of 0 and pi junctions and shows successive phase transitions. The first transition occurs inside each grain at T (c1) = 81 K, and the second transition occurs among the grains at T (c2) = 47 K. A magnetic glass behavior similar to those of spin-glasses is observed at temperatures below T (c2). The memory phenomena are investigated by recording the zero-fieldcooled and thermoremanent magnetizations measured on heating after the cooling process with a halt at T (s) = 41 K. Memory effects of the halt are imprinted in the system when the sample is re-heated. In the case without a field switch at T (s) , the influence of the halt is confined to a narrow temperature region near T (s) whereas the memory effect of the halt employing a field switch is extended over a wide temperature region below T (s) . The results suggest that chiral-glass ordering occurs at T (c2) in the ceramic YBCO.

• 出版日期2013-7