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تسجيل مستخدم جديدAcoustic signatures of the phases and phase transitions in Yb$_2$Ti$_2$O$_7$
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We report on measurements of the sound velocity and attenuation in a single crystal of the candidate quantum- spin-ice material Yb$_2$Ti$_2$O$_7$ as a function of temperature and magnetic field. The acoustic modes couple to the spins magneto-elastically and, hence, carry information about the spin correlations that sheds light on the intricate magnetic phase diagram of Yb$_2$Ti$_2$O$_7$ and the nature of spin dynamics in the material. Particularly, we find a pronounced thermal hysteresis in the acoustic data with a concomitant peak in the specific heat indicating a possible first-order phase transition at about $0.17$ K. At low temperatures, the acoustic response to magnetic field saturates hinting at the development of magnetic order. Furthermore, mean-field calculations suggest that Yb$_2$Ti$_2$O$_7$ undergoes a first-order phase transition from a cooperative paramagnetic phase to a ferromagnet below $Tapprox 0.17$ K.
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In the quest to realize a quantum spin liquid (QSL), magnetic long-range order is hardly welcome. Yet it can offer deep insights into a complex world of strong correlations and fluctuations. Much hope was placed in the cubic pyrochlore Yb$_2$Ti$_2$O$
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