{"paper":{"title":"Anomalous peak effect in iron-based superconductors Ba$_{1-x}$K$_x$Fe$_2$As$_2$ ($x \\approx$ 0.69 and 0.76) for magnetic-field directions close to the $ab$ plane and its possible relation to the spin paramagnetic effect","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cond-mat.supr-con","authors_text":"Akira Iyo, Andhika Kiswandhi, Chul-Ho Lee, Eun-Sang Choi, Hiroshi Eisaki, Kunihiro Kihou, Naoki Kikugawa, Shigeyuki Ishida, Shinya Uji, Taichi Terashima","submitted_at":"2018-09-04T01:14:07Z","abstract_excerpt":"We report magnetic torque measurements on iron-pnictide superconductors Ba$_{1-x}$K$_x$Fe$_2$As$_2$ ($x \\approx$ 0.69 and 0.76) up to an applied field of $B_a$ = 45 T. The peak effect is observed in torque-vs-field curves below the irreversibility field. It is enhanced and becomes asymmetric as the field is tilted from the $c$ axis. For field directions close to the $ab$ plane, increasing- and decreasing-field curves peak at markedly different fields, and exhibit a sharp jump, suggestive of a first-order phase transition, on the high- and the low-field side of the peak, respectively. Complicat"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1809.00762","kind":"arxiv","version":3},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}