High field paramagnetic effect in YBCO single crystals with different oxygen contents

27th International Conference on Low Temperature Physics

Peña, J.P.^1 ; Freitas, O.J.^2 ; Pureur, P.^1

Instituto de Física, Universidade Federal Do Rio Grande Do sul, Av. Bento Gonçalves 9500, Porto Alegre, RS, Brazil^1

Centro Universitrio Metodista IPA, Rua Coronel Joaquim Pedro Salagado 80, Porto Alegre, RS, Brazil^2

关键词: Constant magnetic fields;    Field dependence;    Fixed temperature;    Oxygen concentrations;    Paramagnetic effect;    Temperature decrease;    Temperature intervals;    Zero-field cooling;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/568/2/022036/pdf
DOI  :  10.1088/1742-6596/568/2/022036

来源: IOP

【 摘 要 】

Magnetization vs. temperature measurements were carried out on superconducting YBa2Cu3Ox(YBCO) single crystals. Samples with oxygen concentrations corresponding to x 6.90, 6.85, 6.78 and 6.72 were studied. Zero field cooling (ZFC), field cooled cooling (FCC) and field cooled warming (FCW) prescriptions were employed. Measurements were performed in The temperature interval between 20 K and 120 K in constant magnetic fields ranged from 0.05 T to 5 T. A negative slope was observed in The FCC and FCW curves below a field-dependent minimum located in temperatures less than The irreversibility point (Tirr). This negative slope is identified as The high-field paramagnetic effect (HFPE). With a fixed magnetic field, The magnitude of The observed HFPE increases as The temperature decreases. The field dependence of The HFPE at fixed temperatures is not trivial. The overall magnitude of The measured HFPE depends on The oxygen content and becomes smaller when x decreases. The results are discussed on The basis of The effects of flux compression and spin moment polarization inside The vortex cores.