溫度常被用來衡量相變是否會發生，因為溫度所導致的熱擾動會影響系統內部的物理性質，是驅動相變的重要因素之一。在古典力學的架構下，當溫度為絕對零度時，相變是不可能發生的。然而，由於量子力學的不確定性原理所產生的量子擾動，使得在絕對零度發生相變成為可能。這種由於量子擾動主導所發生的相變稱為量子相變，此時的相變點又稱量子臨界點，在這種相變點附近，經常會發現不符合費米液體的物理行為以及非常規超導現象。然而在實驗上，發現的鐵磁性的量子臨界點卻相對稀少。Belitz, Kirkpatrick, 和Vojta三人透過理論分析解釋該現象的原因，並預測可以透過化學無序的方式來達到量子臨界點。在這份研究當中，我們透過元素 Mo 置換掉部分的 鐵磁元素Ni，來增加系統內的無序程度，以此來降低鐵磁相變溫度，並透過比熱、磁性以及電阻等，研究Ni1−xMox系統接近絕對零度時的行為。我們發現在系統的無序性提高後，磁性行為有減弱的跡象，並在比熱數據出現了發散的非費米液體行為，說明系統逐漸由熱擾動轉變為量子擾動主導。然而，在 x = 0.095，系統出現了自旋玻璃行為，這是因為無序性過大所導致，使得系統由長程有序轉變為短程有序，與量子臨界點的物理行為並不相同，因此我們認為Ni1−xMox系統並不存在鐵磁性的量子臨界點。

Temperature is often used to determine whether a phase transition will occur because the thermal fluctuations caused by temperature affect the physical properties within a system, making it a key factor in driving phase transitions. In the framework of classical mechanics, phase transitions are impossible at absolute zero temperature. However, due to the uncertainty principle of quantum mechanics, quantum fluctuation can cause phase transitions even at 0 K. These transitions, dominated by quantum fluctuation, are known as quantum phase transitions, with the transition points referred to as quantum critical points (QCP). Near these points, non-Fermi liquid behavior and unconventional superconductivity are often observed. Experimentally, however, ferromagnetic quantum critical points are relatively rare. Belitz, Kirkpatrick, and Vojta theoretically explained this phenomenon and predicted that a quantum critical point could be achieved through chemical disorder.
In this study, we increased the disorder in the system by partially substituting Mo for Ni, thereby lowering the ferromagnetic phase transition temperature. We examined the behavior of the Ni1−xMox system near absolute zero through specific heat, magnetism, and electrical resistance measurements. Our findings indicate that increasing disorder weakens the magnetic behavior, and divergent non-Fermi liquid behavior wasobserved in the specific heat data, suggesting that the system is transitioning from thermal fluctuation dominance to quantum fluctuation dominance. However, at x = 0.095, the system exhibited spin-glass behavior due to excessive disorder, causing the system to shift from long-range to short-range order, which differs from the physical behavior of a QCP. Therefore, we conclude that the Ni1−xMox system does not exhibit a ferromagnetic QCP.

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