The ground-state magnetic properties of hexagonal equiatomic alloy of nominal composition Mn_{0.8}Fe_{0.2}NiGe were investigated through dc magnetization and heat capacity measurements. The alloy undergoes first order martensitic transition below 140 K with simultaneous development of long range ferromagnetic ordering from the high temperature paramagnetic phase. The undoped compound MnNiGe has an antiferromagnetic ground state and it shows martensitic like structural instability well above room temperature. Fe doping at the Mn site not only brings down the martensitic transition temperature, it also induces ferromagnetism in the sample. Our study brings out two important aspects regarding the sample, namley (i) the observation of exchange bias at low temperature, and (ii) spin glass like ground state which prevails below the martensitic and magnetic transition points. In addition to the observed usual relaxation behavior the spin glass state is confirmed by zero field cooled memory experiment, thereby indicating cooperative freezing of spin and/or spin clusters rather than uncorrelated dynamics of superparamagnetic like spin clusters. We believe that doping disorder can give rise to some islands of antiferromagnetic clusters in the otherwise ferromagnetic background which can produce interfacial frustration and exchange pinning responsible for spin glass and exchange bias effect. A comparison is made with doped rare-earth manganites where similar phase separation can lead to glassy ground state.
AC magnetic susceptibility study of a sigma-phase Fe65.9V34.1 alloy
研究了σ相Fe 65.9 V 34.1合金的交流磁化率随温度、频率和外加磁场的变化规律。有证据表明，它的磁性表现出折返行为的特征，即两个转变：第一次是在TC约312K时由顺磁态转变为共线铁磁态，第二次是在Tf约302K时转变为混合态（有时称为铁磁再入自旋玻璃），最后，在较低的温度（TRSG约60 K）转变为副本对称性被打破的状态。的Tf的频率依赖性是低于典型的自旋玻璃，一个功能，在光的高浓度的磁性载流子，可以理解的磁性集群之间的弱耦合。
Mesoscopic Magnetic States in Metallic Alloys with Strong Electronic Correlations: A Percolative Scenario for CeNi$_{1-x}$Cu$_{x}$
我们提出的证据存在的强相关合金系统CeNi $_{1-x}$ Cu $_{x}$（0.7 $\le$ x $\le$ 0.2）的小角中子散射实验的基础上，以及在非常低的温度（100 mK）磁化测量的阶梯状磁滞循环的发生约20欧姆的磁性团簇。一个不寻常的功能是观察到的远程铁磁秩序低于集群玻璃化转变没有任何迹象表明在居里温度急剧转变。这些观测结果强烈支持一个唯象模型，其中一个双折射过程连接在高温下观察到的团簇玻璃态与在非常低的温度下通过中子衍射实验观察到的长程铁磁顺序。该模型可以解释所有令人困惑的宏观和微观数据先前在这个系统中获得的，提供了一个新的视角与其他合金化合物的磁性基态与小磁矩或弱铁磁性与内在的无序效应。
Anomalous Ground State in Fe$_{1-x}$Ni$_{x}$ Invar alloys
本文报道了Fe $_{1-x}$ Ni $_x$（x= 0.2，0.3，0.4，0.5，0.6，0.7，0.9）合金的高分辨X射线光电子能谱学（XPS）研究。除了因瓦合金（x=0.4）外，合金的芯能级和俄歇转变没有表现出可观察到的温度引起的变化。因瓦合金在低于20 K的温度下表现出强烈依赖于核心水平的核心水平的变化。这种芯能级随温度的变化归因于自旋玻璃样相的沉淀低于20 K，只有在因瓦合金。Ni L $_3$ M $_{45}$ M $_{45}$的俄歇转变也支持这种沉淀。
Sustained phase separation and spin glass in Co-doped K$_{x}$Fe$_{2-y}$Se$_{2}$ single crystals
本文研究了KPDMATHABMM Fe $_{2-y-z}$ Co $_{z}$ Se $_{2}$（0.06 $\leq$ $z$ $\leq$ 1.73）单晶合金中Co的替代效应。通过3.5%的Co掺杂抑制了超导电性，而半导体K $_{2}$ Fe $_{4}$ Se $_{5}$和超导/金属K $_{x}$ Fe $_{2}$ Se $_{2}$的相分离仍然存在。结果表明，超导相（条纹相）的排列和分布与K、Fe和Co原子的排列有关。半导体自旋玻璃被发现在超导状态附近，持续大的Co浓度。在高Co浓度下，在自旋玻璃上方出现铁磁金属态。这与条形导电相的晶胞、排列和连通性的变化相一致。
