Co ∕ Pt multilayers with large coercivity and small grains

Abstract

Multilayers of [Co∕Pt]20, with tCo∕tPt≐7 and the period Λ in the range of 0.27–0.69nm, and [Co(0.46nm)∕Pt(0.07–0.14nm)]20 have been prepared by sputtering at low deposition rates and a high Ar pressure of 7.8Pa. Structure and magnetic properties were characterized by x-ray diffraction, transmission electron microscopy, magnetometry measurements, and magnetic force microscopy. Column structure, coherent stacking of Co and Pt layers, and small grains have been observed. The average atomic interplane distance d111 changes with the constituent layer thickness. In the first series of Co∕Pt multilayers, the out-of-plane coercivity gradually increases to reach a maximum, with the bilayer period increasing from 0to0.58nm, and decreases with further increasing period. For the second series, the out-of-plane coercivity increases to reach a maximum of 6.5kOe with tPt increasing from 0.07to0.13nm and decreases with further increasing tPt. In order to explain the strong magnetic perpendicular anisotropy, the magnetoelastic energy of CoPt alloy layers must be taken into account.

Tunable interface anisotropy in a Pt/Co1−xFex/Pt multilayer

“…As reported before, K eff mainly comes from the interfacial anisotropy due to the lowered symmetry at the interface. [18] 1250 The in-plane saturation field and anisotropy field are both equal to 2K S /M S . [19] In order to obtain the interfacial 067504-2 anisotropy K S , the saturation magnetization M S is measured.…”

“…The PMA in the Co/Pt multilayers is believed to come from Co/Pt interface anisotropy and Co bulk anisotropy. [1] The total effective magnetic anisotropy energy is often defined as [10,17,18]…”

Effect of swift heavy ion irradiation in Fe/W multilayer structures

“…Hysteresis loop corresponding to higher fluence shows increasing trend of H c as compared to lower dose irradiated MLS. Here the dominating factor is roughness, i.e., interlayer roughness as well as roughness of individual layer [33][34][35]. The change in interlayer roughness can be directly compared from Table 1.…”

Magnetic measurements in thin film specimens: Rejecting the contribution of the substrate

“…Probably one of the most widely studied category of such artificial specimens is in the form of thin films . Sputtering [5,6,[8][9][10][12][13][14][17][18][19][20], laser ablation [15,16,33,[36][37][38], molecular beam epitaxy [4,11] or other techniques are usually employed for their preparation, so that the produced samples to exhibit the desired properties.…”

“…Decoupling phenomena observed in the area of superconductivity, enhancement of the magnetic anisotropy or modulation of magnetic domains may be observed when the artificial samples are prepared only in bi-layer or multi-layer thin film form [9,[14][15][16][32][33][34][35][36][37][38] or when patterned in stripes of width lower than some critical length scale [17]. Another category of films widely studied today is the one of films that host dots, squares or other type of shapes with dimensions in the nanometer scale [4,7,8,12,13,[21][22][23][24][25][26][27].…”