Abstract
The FeNi(30 nm)/FeMn(20 nm) bilayers were deposited by magnetron sputtering at room temperature onto glass substrates in a magnetic field. Afterward, they were subjected to heat treatments at temperatures from 50 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$^{\circ}{\rm C}$ </tex-math></inline-formula> to 400 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$^{\circ}{\rm C}$ </tex-math></inline-formula> in vacuum or in a gas mixture containing oxygen. The as-deposited FeNi/FeMn bilayers presented an exchange bias field <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">${H}_{{\rm ex}}=30~{\rm Oe}$ </tex-math></inline-formula> , a coercivity <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$H_{{\rm c}}\approx 3~{\rm Oe}$ </tex-math></inline-formula> , and a blocking temperature <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$T_{{\rm b}}\approx 140^{\circ}{\rm C}$ </tex-math></inline-formula> . An increase of the annealing temperature results in a monotonous decrease of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$H_{{\rm ex}}$ </tex-math></inline-formula> for temperatures up to 200 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$^{\circ}{\rm C}$ </tex-math></inline-formula> . For higher annealing temperatures, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$H_{{\rm ex}}$ </tex-math></inline-formula> remains almost constant. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$H_{{\rm c}}$ </tex-math></inline-formula> sharply increases in the range from 200 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$^{\circ}{\rm C}$ </tex-math></inline-formula> to 300 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$^{\circ}{\rm C}$ </tex-math></inline-formula> , and finally decreases dramatically upon annealing <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">${>}{300}^{\circ}{\rm C}$ </tex-math></inline-formula> . Preferential surface oxidation of Mn during heat treatment in a gas mixture results in the formation of the ferromagnetic <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$\alpha$ </tex-math></inline-formula> -Fe(Mn) phase and leads to the change of the magnetic moment of the samples. The adjustment of temperature and annealing time in a gas mixture allows us to increase the switching field value of exchange biased FeNi/FeMn bilayers.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
