Flux pinning by Y2BaCuO5 precipitates and field- and temperature-driven pinning centers in melt-powder-melt-growth processed YBa2Cu3O7.
Flux pinning by Y2BaCuO5 precipitates and field- and temperature-driven pinning centers in melt-powder-melt-growth processed YBa2Cu3O7.
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Y2BaCuO5 沉淀物的通量钉扎以及熔体粉末熔体生长处理的 YBa2Cu3O7 中场和温度驱动的钉扎中心。
DOI：
10.1103/physrevb.48.13922
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Tanaka
中科院分区：
文献类型：
--
作者：
Kung;Maley;Mchenry;Willis;Murakami;Tanaka
熔体-粉末-熔体-生长过程中的磁滞、磁通钉住和磁通蠕变${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ （Y 1:2:3）含有标称的0、25和40 mol % concentration of ${\mathrm{Y}}_{2}$${\mathrm{BaCuO}}_{5}$ (Y 2:1:1) inclusions were investigated. The strong pinning due to 2:1:1-phase precipitates in these samples allows for characterization of the hysteretic response as a function of pinning-site concentration over a large portion of magnetic-field\char21{}temperature space. We have found the following: (i) The curves of effective pinning energy ${\mathit{U}}_{\mathrm{eff}}$ versus current density J reveal a diverging behavior of ${\mathit{U}}_{\mathrm{eff}}$(J) in the low-J regime. This supports the existence of a vortex-glass state, and is a signature of a vanishing resistance as the current density approaches zero. (ii) Both the ${\mathit{U}}_{\mathrm{eff}}$ and the J values obtained from magnetic hysteresis loops were observed to increase with Y 2:1:1 concentration. The appearance of the butterfly-shaped (or ``fishtail'') hysteresis loops indicates a ${\mathit{J}}_{\mathit{c}}$ that is an increasing function of H (or B). Moreover, it has been demonstrated that the additional pinning leads to an increase in ${\mathit{U}}_{\mathrm{eff}}$ in an H-T region in which the butterfly is developed.
Magnetic hysteresis, flux pinning, and flux creep in melt-powder-melt-growth processed ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ (Y 1:2:3) containing nominal 0, 25, and 40 mol % concentration of ${\mathrm{Y}}_{2}$${\mathrm{BaCuO}}_{5}$ (Y 2:1:1) inclusions were investigated. The strong pinning due to 2:1:1-phase precipitates in these samples allows for characterization of the hysteretic response as a function of pinning-site concentration over a large portion of magnetic-field\char21{}temperature space. We have found the following: (i) The curves of effective pinning energy ${\mathit{U}}_{\mathrm{eff}}$ versus current density J reveal a diverging behavior of ${\mathit{U}}_{\mathrm{eff}}$(J) in the low-J regime. This supports the existence of a vortex-glass state, and is a signature of a vanishing resistance as the current density approaches zero. (ii) Both the ${\mathit{U}}_{\mathrm{eff}}$ and the J values obtained from magnetic hysteresis loops were observed to increase with Y 2:1:1 concentration. The appearance of the butterfly-shaped (or ``fishtail'') hysteresis loops indicates a ${\mathit{J}}_{\mathit{c}}$ that is an increasing function of H (or B). Moreover, it has been demonstrated that the additional pinning leads to an increase in ${\mathit{U}}_{\mathrm{eff}}$ in an H-T region in which the butterfly is developed.