Study of ferro-antiferromagnetic transition in [001]-oriented L1 FePt1−xRhx film

Abstract

Magnetic properties of [001]-oriented L10 FePt1−xRhx films (tFePtRh=6.12 nm) with Rh composition (x) of 0≤x≤0.40 were studied, and the magnetic phase in a composition-temperature plane was investigated. At room temperature, the films with 0≤x≤0.32 were in a ferromagnetic (FM) phase with a coercivity of several kilo-oersteds, and the films with 0.34≤x≤0.40 were in an antiferromagnetic (AF) phase. At x=0.32, which is close to the critical composition of the FM-AF transition at room temperature, the uniaxial magnetocrystalline anisotropy (Ku) was about 1.7×107 erg/cm3. A bit patterning process using the discontinuous FM-AF transition was studied. First, microfabricated FePt square films (1.7 nm thick) were prepared on the AF FePt0.64Rh0.36 film (6.7 nm thick). Second, those square films and the FePt0.64Rh0.36 film were mixed by annealing. The Fe and Pt atoms were thermally diffused into the FePt0.64Rh0.36 film locally, and the composition of the diffused areas changed to FM FePt0.72Rh0.28. A magnetic force microscopy study suggested that only the diffused areas changed from AF to FM phase. A minimum FM dot size of 300×300 nm2 was realized, and the FM dots were multidomain structures.

Dependence of magnetic properties on the film thickness and Pt atomic fraction of post-annealed Fe1−xPtx-C granular films on MgO(100) and SiO2/Si(100) substrates

“…Recently, the nonmagnetic matrixes including C, SiO 2 , TiO 2 , Ta 2 O 5 and SiN x have been used to isolate the FePt grains for decreasing the signal-to-noise ratio [12][13][14][15][16]. The metal elements such as Cr, Cu, Ru and Ag were added in the FePt alloy to improve the phase transition and the ordering of the fct phase [17][18][19][20]. Meanwhile, multiple laser pulsing and ultrafast heating were used to make the phase transition into the ordered fct FePt phase [21,22].…”

Fabrication of [001] L1-FePtRh ferro-antiferromagnetic pattern by flat-patterning method

“…The resultant L1 0 FePt 1-x Rh x film has a high K u value and exhibits an FM-AF transition. 9 Films with x values in the ranges of 0-0.32 and 0.34-0.40 are FM and AF, respectively, at room temperature. The AF phases are stable at lower temperatures, while the FM or PM phases are stable at higher temperatures.…”

Tuning the Curie temperature of L1 ordered FePt thin films through site-specific substitution of Rh

“…3,10 A study on the ferromagnetic-paramagnetic (PM) and/or FM-AFM transitions in this system reported that T C underwent a monotonic decrease with Rh doping. 11 The underlying mechanism determining T C and the temperature dependent K u of the Rh doped FePt system remains unclear. Specifically, the effects of Rh substitution on the SRO of FePt thin films and associated electronic exchange interactions of neighboring atoms on T C are of interest.…”