Multiple magnetic phase transitions in Ce(Cu1-xNix)2Ge2

Evolution of magnetism and superconductivity in CeCu2(Si1−xGeTrovarelli1, Weiden2, Müller-Reisener3 et al. 1997Phys. Rev. BSelf Cite627592View full textAdd to dashboardCite

“…18 In this alloy, the first-order character of this transition has been clearly demonstrated by C P (T) and ␣(T) measurements on single crystals. 25 Further, an anomaly at T p Ӎ2.2 K was also observed in (T) measurements on pure CeCu 2 Ge 2 under hydrostatic pressure at Pу1.3 GPa. 26 The replacement of Cu by Ni in CeCu 2 Ge 2 corresponds to a strong change in the electronic states, whereas the substitution of Ge by Si or the application of external pressure should have only minor effect.…”

“…However, recent ␣(T) results on a single crystal indicate a first weak anomaly at T ␣ ϭ2.4 K and a strong irreversibility below TӍ1.5 K, indicating some instabilities of the magnetic structure at low temperatures. 25 Recent neutron scattering measurements suggest that the transition below 1.5 K is a lock-in transition to a commensurate structure, whereas no anomalous changes in the propagation vector were observed above 1.5 K. 29 A small reorientation of the moments cannot, however, be excluded from these neutron experiments, since the intensity of only a few reflexes have been recorded as a function of temperature. The same magnetic structure as that of CeCu 2 Ge 2 at 1.5 K was observed for xϭ0.8 and xϭ0.6 at 1.6 K except for the decrease of the ordered moments and a slight change of the propagation vector.…”

Spin fluctuations and non-Fermi-liquid behavior ofCeNi2Ge2

“…For T < 5 K, i.e., well below T K , CeNi 2 Ge 2 exhibits NFL behavior with C/T ∝ ln(T 0 /T ) and ρ − ρ 0 ∝ T x , where 1 < x < 1.5 [9]. CeNi 2 Ge 2 also displays superconductivity near the QCP [13] which may be spin-fluctuation mediated [14].The NFL behavior has been thought to be caused by the spin fluctuations being slowed down by a QCP of an antiferromagnetic phase, which would be one of those observed in Pd, Rh, or Cu substituted compounds [15,16,17]. However, previous neutron-scattering experiments [18] on single crystalline CeNi 2 Ge 2 disagree with this simple interpretation.…”

“…The NFL behavior has been thought to be caused by the spin fluctuations being slowed down by a QCP of an antiferromagnetic phase, which would be one of those observed in Pd, Rh, or Cu substituted compounds [15,16,17]. However, previous neutron-scattering experiments [18] on single crystalline CeNi 2 Ge 2 disagree with this simple interpretation.…”

Effect of Co-Doping on the Magnetic Ground State of the Heavy-Fermion System CeCu2Ge2 Studied by Neutron Diffraction

“…Over the past few decades, heavy-fermion systems containing a sub-lattice of 4 f or 5 f elements have been intensively studied [1][2][3][4][5][6][7][8][9][10]. Competing interactions often reveal different ground-state properties in these compounds.…”