Single crystal synthesis and magnetic properties of Co²⁺-substituted and non-substituted magnetoplumbite-type Na–La ferrite

Single crystals of magnetoplumbite-type Na–La ferrite with and without Co doping were grown by the flux method. Wave length dispersive X-ray analysis reveals that Na and La are present in the ratio of Na/La ​= ​0.25–0.41, and Co is successfully substituted for Fe. Magnetization measurements using single crystals indicate uniaxial magnetic anisotropy in these materials. A metamagnetic transition for the hard-axis magnetization was observed in non Co²⁺-substituted samples at around 7 ​kOe due to the magnetic free energy double minima originating from the Fe²⁺ ion. The successful introduction of Co²⁺ enhances the uniaxial magnetic anisotropy favorable for permanent magnets

Novel slow dynamics of phase transition in the partially ordered frustrated magnet DyRu2Si2

DyRu2Si2 is a frustrated magnet to exhibit multiple magnetic phase transition in zero and finite magnetic fields. We investigated and characterized the phase transition between the partially-ordered antiferromagnetic phases at zero field by ac susceptibility measurements. Detailed ac susceptibility measurements reveal the novel critical dynamics of the phase transition; extremely slow dynamics with the relaxation time in the order of 10-100 msec, speed-up of the dynamics on cooling indicating its non-thermally activated origin and growing of the ferromagnetic correlations towards the phase transition temperature. On the basis of these findings, we propose the novel phase transition process, namely, the spontaneous striped-arrangement of the precedently emergent "belt-like" ferromagnetic spin texture.Comment: Accepted by JPSJ URL:https://journals.jps.jp/doi/10.7566/JPSJ.92.09470

Extended resection for appendicitis

Background : Appendectomy can be challenging and occasionally converted to extensive resection for complicated appendicitis. However, optimal treatment strategies can be developed using preoperative risk assessment. Thus, we aimed to investigate the preoperative predictors of extensive resection in complicated appendicitis patients undergoing surgery. Materials and methods : In total, 173 complicated appendicitis patients undergoing surgery between 2014 and 2019 were classified into the appendectomy (n = 153) or extensive resection (n = 20) groups. Clinicopathological factors and surgical outcomes were compared between groups. Results : Extensive resection was performed in 20 of 173 complicated appendicitis patients (11.5%). The rates of having defects in the wall structure at the appendix root on computed tomography images were significantly higher, and the duration from onset to surgery was significantly longer in the extensive resection group. Significant differences were found in operative duration, blood loss and postoperative hospitalization, but none in the incidence of postoperative complications between groups. Multivariate analyses showed that defects in the wall structure at the appendix root and five days or longer from onset were identified as independent predictors of extensive resection. Conclusions : Defects in the wall structure at the appendix root and five days or longer from onset predict extensive resection performance in complicated appendicitis patients

Doping Dependence of the in-Plane Transition in Co3_3Sn2_2S2_2

In Co$_3$Sn$_2$S$_2$ two transitions are observed, the main one to a ferromagnetic state at $T_C = 174$ K and the second one, involving in-plane components at $T_P = 127$ K. We follow their doping dependence as Sn is replaced with In, which causes a reduction of $T_C$ and $T_P$. Importantly, both transitions follow the same doping dependence, indicating a single energy scale involved with both processes.Comment: accepted as a short note in JPSJ; a continuation of work published in arXiv:2211.01483 and https://doi.org/10.1103/PhysRevB.106.L18040