Magnetic Proximity Effects in Antiferromagnet/Ferromagnet Bilayers: The Impact on the Néel Temperature

Abstract

We present a study of the ordering temperature of an ultrathin antiferromagnetic film in the proximity of a ferromagnetic layer. The Néel temperature of a single-crystalline antiferromagnetic FexMn1-x film on Cu(001) in contact with a ferromagnetic Ni layer was monitored by the discontinuity in the coercivity as a function of temperature by magneto-optical Kerr effect measurements. It decreases by up to 60 K if the magnetization axis of the ferromagnet is switched from out of plane to in plane by deposition of a Co overlayer. These results give clear evidence for a magnetic proximity effect in which the ferromagnetic layer substantially influences the ordering temperature of the antiferromagnetic layer.

Anomalous magnetic properties of 7 nm single-crystal Co3O4 nanowires

“…Due to the magnetic core-shell exchange interactions, the Néel temperature of the Co 3 O 4 AFM core was also enhanced from about 40 K to T 2 ~ 56 K. Recently, similar magnetic proximity effect was proposed in Ref. [15,17] and observed in antiferromagnetic/ferrimagnetic core-shell nanoparticles.…”

“…The enhancement of T N of AFM core from about 40 K to 56 K is tentatively attributed to core-shell exchange interactions, i.e., the so-called magnetic proximity effect proposed in Ref. [15,17]. The Co 3 O 4 nanowire shell shows macroscopic residual magnetic moments below 35 K. Cooling the nanowires in a magnetic field larger than 20 kOe, up to 16% of the residual moments is tightly pinned to the antiferromagnetic lattice and does not rotate in an external magnetic field, which results in an obvious horizontal (exchange bias field H E ) and vertical shift of hysteresis loop.…”

“…Since that time, there has been a continuously growing interest in both the fundamental physics and applications of this effect [3][4][5]. Several decades later, new phenomena, such as positive exchange bias and exchange bias in nanoscale antiferromagnetic (AFM) system, are still being uncovered in this subject [6][7][8][9][10][11][12][13][14][15][16][17].…”

Magnetic proximity effect in Pr0.5Ca0.5MnO3/La0.7Sr0.3MnO3 bilayered films

“…One of a principal effect provided by the magnetic coupling between the FM and the AFM layers is manifested by a shift of the hysteresis loop along the field axis of a ferromagnet, and is termed as the exchange bias interaction [2,3]. At the same time the mutual influence between adjacent FM/AFM layers can significantly modify a thermodynamic behavior of these objects in the wide temperature range [4]. Furthermore, a magnetic proximity effect can occur due to the interaction between two magnetic layers with different FM spin-ordering temperatures ( ).…”

Exploiting interfacial and size effects to construct oxide superlattices with robust and tunable magnetoelectric properties at room temperature

“…Due to the exchange interactions across the interface, the FM layers can be expected to be partly ordered above T . (Note that proximity and size effects of this kind are typical of magnetic superlattices and bilayers [20,21].) Furthermore, ferroelectricity can be effectively induced in a SL structure, e.g.…”