论文标题
低温磁相变的量子与经典性质，tbal $ _3 $（bo $ _3 $）$ _ 4 $
Quantum versus classical nature of a low-temperature magnetic phase transition in TbAl$_3$(BO$_3$)$_4$
论文作者
论文摘要
特定的热量，$ c_b $，tbal $ _3 $（bo $ _3 $）$ _ 4 $ Crystal，以50 mk $ <t <$ 300 k进行了研究，重点是$ t <1 $ k，在$ t_c = 0.68 $ k. nock. noc，nor-phonon（$ c_m $）和$ coditions $ coditions $ t_c = 0.68 $ t_c = 0.68 $ k.发现了$ t_c $的降低磁场，平行于易于磁化轴，$ b_ {||} $。已经确定，$ c_m $和grüneisen比率取决于$ b_ {|||} $和$ t $以某种方式的特征，其中经典的过渡是由QF QF驱动的，qf，qf，$ t = 0 $的量子关键点，通过调谐控制参数（$ b_ = $ b_ {|| ||）。构建了$ b_ {||} - t $相图，并评估了动态关键指数$ 0.82 \ le z \ le 0.96 $。过渡的性质尚未明确确定。磁化研究指向TB $^{3+} $磁矩的铁磁顺序，但是，$ t_c $降低$ t_c $，$ b_ {||} $增加与经典行为相反。因此，应该认为QF的主要作用。
Specific heat, $C_B$, of a TbAl$_3$(BO$_3$)$_4$ crystal was studied for 50 mK $<T<$ 300 K, with emphasis on $T<1$ K, where a phase transition was found at $T_c =0.68$ K. Nuclear, non-phonon ($C_m$), and lattice contributions to $C_B$ were separated. Lowering of $T_c$ with ncrease of magnetic field parallel to the easy magnetization axis, $B_{||}$, was found. It was established that $C_m$ and a Grüneisen ratio depend on $B_{||}$ and $T$ in a way characteristic of systems, in which a classical transition is driven by quantum fluctuations, QF, to a quantum critical point at $T=0$, by tuning a control parameter ($B_{||}$). The $B_{||} - T$ phase diagram was constructed and the dynamical critical exponent $0.82 \le z \le 0.96$ was assessed. Nature of the transition was not established explicitly. Magnetization studies point at the ferromagnetic ordering of Tb$^{3+}$ magnetic moments, however, lowering of $T_c$ with increase in $B_{||}$ is opposite to the classical behavior. Hence, a dominant role of QF was supposed.
