论文标题
y $ _ {0.9} $ gd $ _ {0.1} $ _ {0.1} $ fe $ _ {2} $ h $ _ {x} $ hydrides
Magnetic, structural and magnetocaloric properties of Y$_{0.9}$Gd$_{0.1}$Fe$_{2}$H$_{x}$ hydrides
论文作者
论文摘要
At 300 K, Y$_{0.9}$Gd$_{0.1}$Fe$_{2}$H$_{x}$ hydrides crystallize sequentially with increasing H concentration in various structures related to a lowering of the cubic MgCu$_{2}$ type structure of the parent alloy: cubic C1, monoclinic M1, cubic C2, monoclinic M2，立方C3，OrthorhombicO。在300 K以上，它们在T $ _ {o-d} $温度下进行一阶转变，该温度由氢原子的订单序列驱动到间隙位点。通过磁测量以及高分辨率同步加速器衍射实验，已经研究了它们的磁性，结构和磁化特性。 5 K时的磁化量从4略微降低到3.8 $μ__{b} $，x = 3至3.9 h f.u.，然后用更大的斜率用于较高的h含量。观察到磁性过渡温度的不连续降低：M1和C2氢化物是铁磁性的，T $ _ {C} $接近300 K，M2 Hydride在T $ _ {FM-AFM} $ = 144 K的T $ _ {FM-AFM} $ = 144 k和ODRIDES A Hydrides a Shartide a Hydrides a hydrides a的敏捷性 - 磁性 - 抗磁性过渡均具有敏锐的速度。磁化达到RT。负磁熵变体（$δ$ s $ _ {m} $）在M1和C2阶段接近T $ _ {C} $，接近M2阶段的T $ _ {FM-AFM} $，而由于$ S $ _ {M} $ peeps n $ peeps n $ d $ d $ ___提出了结构和磁相图。
At 300 K, Y$_{0.9}$Gd$_{0.1}$Fe$_{2}$H$_{x}$ hydrides crystallize sequentially with increasing H concentration in various structures related to a lowering of the cubic MgCu$_{2}$ type structure of the parent alloy: cubic C1, monoclinic M1, cubic C2, monoclinic M2, cubic C3, orthorhombic O. Above 300 K, they undergo a first-order transition at a T$_{O-D}$ temperature driven by order-disorder of hydrogen atoms into interstitial sites. Their magnetic, structural and magnetocaloric properties have been investigated through magnetic measurements, and high-resolution synchrotron diffraction experiments. The magnetization at 5 K decreases slightly from 4 to 3.8 $μ_{B}$ for x = 3 to 3.9 H f.u., then with a larger slope for higher H content. A discontinuous decrease of the magnetic transition temperature is observed: M1 and C2 hydrides are ferrimagnetic with T$_{C}$ near 300 K, M2 hydride displays a sharp ferromagnetic-antiferromagnetic transition at T$_{FM-AFM}$ =144 K, whereas C3 and O hydrides present only a sharp increase of the magnetization below 15 K and a weak magnetization up to RT. Negative magnetic entropy variations ($Δ$S$_{M}$) are measured near T$_{C}$ for the M1 and C2 phases, near T$_{FM-AFM}$ for the M2 phase, whereas positive $Δ$S$_{M}$ peaks due to inverse MCE effect are found near T$_{O-D}$. A structural and magnetic phase diagram is proposed.
