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Register a new userHysteretic superconducting resistive transition in Ba0.07K0.93Fe2As2
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We have observed hysteresis in superconducting resistive transition curves of Ba$_{0.07}$K$_{0.93}$Fe$_2$As$_2$ ($T_csim$8 K) below about 1 K for in-plane fields. The hysteresis is not observed as the field is tilted away from the $ab$ plane by 20$^{circ}$ or more. The temperature and angle dependences of the upper critical field indicate a strong paramagnetic effect for in-plane fields. We suggest that the hysteresis can be attributed to a first-order superconducting transition due to the paramagnetic effect. Magnetic torque data are also shown.
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