Magnetic irreversibility and pinning force density in the Ti-V alloys

Abstract

We present a study of critical current density estimated through dc magnetization measurements in the superconducting alloys Ti60V40 and Ti70V30. The magnetization is irreversible below the irreversibility field (BIrr), which is different from the upper critical field for the alloys. Additionally, the alloys are found to exhibit a peak effect in magnetization below the upper critical field. The critical current densities of the alloys estimated from the magnetization results decrease strongly with increasing magnetic field. The pinning force density follows a universal scaling relation with respect to the magnetic field divided by the BIrr. The field dependence of the pinning force density is analyzed in terms of the size of the grains of the main β phase, the possible presence of dislocation arrays within the grains of the main phase, the presence of additional metallurgical phases, and the configuration of the grain boundaries in the system. The temperature dependence of critical current density is also analyzed within the framework of existing theories.

Grain Refinement and Enhancement of Critical Current Density in the V0.60Ti0.40 Alloy Superconductor With Gd Addition

“…The V0.60-xTi0.40Gdx (x = 0, 0.005, 0.01, 0.02) alloys were prepared by argon-arc-melting of the constituent elements (purity > 99.8%) [3]. Distinct peaks corresponding to both V0.60Ti0.40 and Gd were observed in the X-ray diffraction patterns of the alloys containing Gd.…”

“…They are machinable and have high upper critical field (Hc2(0)) [1,2]. Our previous studies reveal that though the grain boundaries pin the flux lines in these alloys, their is still lower than the commercial superconducting wires [3,4]. The average grain size in these alloys is found to vary from few hundred µm to few mm [4].…”

Doping Dependence of the Second Magnetization Peak, Critical Current Density, and Pinning Mechanism in BaFe2–xNixAs2 Pnictide Superconductors

“…The normalized pinning force density is plotted as a function of reduced magnetic field (h = H/H irr ) in Figure 12a−f and is analyzed using the model developed by Dew-Hughes, 59 which has been widely used in many other studies. 33,57,60,61 The magnetic irreversibility field (H irr ) is extracted by considering the magnetic field value where J c ≤ 50 A/cm 2 , below which the J c decreases to the noise level. The scaling of the normalized pinning force curves shows a single peak for each sample under study.…”

“…To investigate the pinning behavior in BaFe 2– x Ni x As 2 , we estimate the pinning force density using F p = J c × H , where J c is the critical current density and H is the magnetic field. The normalized pinning force density is plotted as a function of reduced magnetic field ( h = H / H irr ) in Figure a–f and is analyzed using the model developed by Dew-Hughes, which has been widely used in many other studies. ,,, The magnetic irreversibility field ( H irr ) is extracted by considering the magnetic field value where J c ≤ 50 A/cm 2 , below which the J c decreases to the noise level. The scaling of the normalized pinning force curves shows a single peak for each sample under study.…”

Noncentrosymmetric superconductivity and peak effect in rhenium based materials

“…At this point, it is not clear why the PE anomalies in the M-H scans should be so small, if any at all, in the remainder Re 3 M samples. Similar findings have been reported for some Ti 1−y V y alloys [208]: clear J M c (H) peaks are observed in the Ti 60 V 40 but become absent when y is decreased to 30 %at., although both alloys were found to exhibit a peak effect in magnetization below the Recently, the PE line has been found to lie in the vicinity of the mean field boundary line in a vanadium single crystal while its order-disorder transition occurs deep in the mixed state.…”