A study of the ferromagnetic transition of $SrRuO_3$ in nanometer thick bilayers with $YBa_2Cu_3O_y$, $La_{1.88}Sr_{0.12}CuO_{4-y}$, Au and Cr: Signature of injected carriers in the pseudogap regime

G. Aharonovich; G. Koren; E. Polturak

doi:10.1103/PhysRevB.76.224514

paper

A study of the ferromagnetic transition of $S r R u O_{3}$ in nanometer thick bilayers with $Y B a_{2} C u_{3} O_{y}$ , $L a_{1.88} S r_{0.12} C u O_{4 - y}$ , Au and Cr: Signature of injected carriers in the pseudogap regime

arXiv:0707.2497 · doi:10.1103/PhysRevB.76.224514

Abstract

The hypothesis regarding the existence of uncorrelated pre-formed pairs in the pseudogap regime of superconducting $Y B a_{2} C u_{3} O_{y}$ is tested experimentally using bilayers of $Y B a_{2} C u_{3} O_{y}$ and the itinerant ferromagnet $S r R u O_{3}$ . In our study, we monitor the influence of $Y B a_{2} C u_{3} O_{y}$ on $T_{p}$ , the ferromagnetic ordering temperature of $S r R u O_{3}$ . Here, $T_{p}$ is the temperature of maximum dM/dT or dR/dT where M and R are the magnetization and resistance of $S r R u O_{3}$ , respectively. We compare the results with similar measurements carried out on bilayers of $L a_{1.88} S r_{0.12} C u O_{4 - y}$ , $A u$ and $C r$ with $S r R u O_{3}$ . We find that in bilayers made of underdoped 10 nm $Y B a_{2} C u_{3} O_{y}$ /5 nm $S r R u O_{3}$ , the $T_{p}$ values are shifted to lower temperatures by up to 6-8 K as compared to $T_{p} \approx 140$ K of the 5 nm thick reference $S r R u O_{3}$ film. In contrast, in the other type of bilayers, which are not in the pseudogap regime near $T_{p}$ , only a smaller shift of up to $\pm$ 2 K is observed. These differences are discussed in terms of a proximity effect, where carriers from the $Y B a_{2} C u_{3} O_{y}$ layer are injected into the $S r R u O_{3}$ layer and vice versa. We suggest that correlated electrons in the pseudogap regime of $Y B a_{2} C u_{3} O_{y}$ are responsible for the observed large $T_{p}$ shifts.

arXiv comment9 figures

A study of the ferromagnetic transition of SrRuO3​ in nanometer thick bilayers with YBa2​Cu3​Oy​, La1.88​Sr0.12​CuO4−y​, Au and Cr: Signature of injected carriers in the pseudogap regime

Abstract

References in corpus (9)

A study of the ferromagnetic transition of $S r R u O_{3}$ in nanometer thick bilayers with $Y B a_{2} C u_{3} O_{y}$ , $L a_{1.88} S r_{0.12} C u O_{4 - y}$ , Au and Cr: Signature of injected carriers in the pseudogap regime