Giant Hall resistance in Pt-based ferromagnetic alloys

Abstract

We report on the observation of a dramatically increased extraordinary Hall Effect in Pt-based ferromagnetic alloy thin films with varying composition and thickness that were deposited using magnetron sputtering. Hall slope as high as 76.8 μΩ cm/T has been obtained at 110 K and 22.6 μΩ cm/T at 300 K. Excellent sensitivity, linearity, and a small temperature coefficient have been achieved in a particular composition, Fe35Pt65, for a film thickness of 10 nm. The optimized Fe–Pt thin films compare favorably with the commonly used semiconductor Hall sensors.

Ultrasensitive anomalous Hall effect in SiO2/Fe-Pt/SiO2 sandwich structure films

“…Different from the ordinary Hall effect caused by the Lorentz force, the anomalous Hall effect (AHE), arising from the spin-orbit interaction of the spin-polarized current carriers in conductive ferromagnetic materials, provides an alternative approach for magnetic sensing. [1][2][3] So far, quite a few magnetic systems with very large or giant AHE have been explored, including rare-earth based amorphous alloy films, 4 Ni-SiO 2 percolating granular films, 5 Pt-based magnetic multilayers and alloy films, [6][7][8] as well as Heusler compound Co 2 MnAl etc. 9,10 However, these systems suffer from either insufficient chemical/thermal stability or unsatisfactory field sensitivity.…”

Submicrometer Hall devices fabricated by focused electron-beam-induced deposition

“…The current sensitivity S I is about 0.9 V / AT in the linear region ͑i.e., below 1 T͒. Since the device thickness is about 50 nm, this corresponds to a Hall coefficient R H of about 5 ϫ 10 −8 ⍀ m/T ͑similar to that reported for Fe-Pt, Fe-Si, Ni, and LaBaMnO 3 thin films, [10][11][12][13][14][15] and Fe-Cr multilayers 16 ͒. The resistance between the bias current contacts varies by less than 0.5% from 0 to 2.2 T. At magnetic inductions higher than 1 T, the Hall voltage saturates ͑above 1 T the Hall voltage varies by only a few microvolts͒.…”

“…5 Magnetic materials show additional "Hall phenomena" which are, generally speaking, generated by spin-orbit interactions: the so-called extraordinary [10][11][12][13][14][15][16] and planar Hall effects.…”

“…[4][5][6][7][8][9] The ordinary Hall effect is due to the Lorentz force acting on charge carriers in metals, semi-metals, and semiconductors. 5 Magnetic materials show additional "Hall phenomena" which are, generally speaking, generated by spin-orbit interactions: the so-called extraordinary [10][11][12][13][14][15][16] and planar Hall effects. [17][18][19][20] The local deposition of materials using a focused electron beam in the presence of a volatile precursor is a wellestablished technique for the maskless fabrication of submicrometer structures such as functionalized tips for scanning probe microscopy, [21][22][23][24][25][26] electrodes for local conductivity measurements, 27 solder bonds for carbon nanotubes studies, 28 nanowires, [29][30][31][32][33] and nanodots.…”

Controlled manipulation of domain walls in ultra-thin CoFeB nanodevices

“…Magnetic materials incorporating heavy elements such as Pt or Au show pronounced AHE due to large spin-orbit interactions within them [8,9]. PMA multilayers including these materials benefit jointly from powerful AHE signals and strong spin transfer torque, this makes them the subject of great interest at present [10,11].…”