Limits...
Cooling field and temperature dependent exchange bias in spin glass/ferromagnet bilayers.

Rui WB, Hu Y, Du A, You B, Xiao MW, Zhang W, Zhou SM, Du J - Sci Rep (2015)

Bottom Line: Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards.In the meanwhile, HFC variation has weak effects on HC.Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.

ABSTRACT
We report on the experimental and theoretical studies of cooling field (HFC) and temperature (T) dependent exchange bias (EB) in FexAu1-x/Fe19Ni81 spin glass (SG)/ferromagnet (FM) bilayers. When x varies from 8% to 14% in the FexAu1-x SG alloys, with increasing T, a sign-changeable exchange bias field (HE) together with a unimodal distribution of coercivity (HC) are observed. Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards. In the meanwhile, HFC variation has weak effects on HC. By Monte Carlo simulation using a SG/FM vector model, we are able to reproduce such HE dependences on T and HFC for the SG/FM system. Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

No MeSH data available.


Related in: MedlinePlus

Cooling field influence on the temperature dependent HE (a) and HC (c) for a Fe11Au89(50 nm)/FeNi(5 nm) sample measured between T = 2 K and 20 K and the corresponding calculated results of HE (b) and HC (d) for the SG/FM bilayers obtained between T = 2.6 K and 19.96 K.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4562234&req=5

f3: Cooling field influence on the temperature dependent HE (a) and HC (c) for a Fe11Au89(50 nm)/FeNi(5 nm) sample measured between T = 2 K and 20 K and the corresponding calculated results of HE (b) and HC (d) for the SG/FM bilayers obtained between T = 2.6 K and 19.96 K.

Mentions: Experimental study of the HFC dependent EB has been performed and representative results are presented in Fig. 3. As displayed in Fig. 3(a,c), when HFC increases from 0.2 kOe to 50 kOe, the HE ∼ T curve shifts toward upper-left while the HC ∼ T curves keep almost overlapped. Accordingly, T0 decreases from 5.5 K to 4.2 K. The peak position of the HE ∼ T curve moves towards lower T slightly and the maximum positive value of HE increases significantly from 10 Oe to 18 Oe. Figure 3(b,d) show the corresponding simulation results. The sign inversion in HE with T can be reproduced and HE ∼ T curve shift can also be repeated. It is noticed that simulated T0, TP, and HE(TP) results have certain deviation from the experiments, but the theoretical HE ∼ T curves agree well with experimental measurements. On the other hand, the calculated trend of HC versus T is different from the experimental results obtained both by Ali et al.21 and us, but in agreement with those reported in ref. 22. Another disagreement with the present experimental results is that the theoretical HC ∼ T curves are HFC-dependent at the temperatures just below TB, i.e., HC for larger HFC is slightly larger. These discrepancies will be addressed later.


Cooling field and temperature dependent exchange bias in spin glass/ferromagnet bilayers.

Rui WB, Hu Y, Du A, You B, Xiao MW, Zhang W, Zhou SM, Du J - Sci Rep (2015)

Cooling field influence on the temperature dependent HE (a) and HC (c) for a Fe11Au89(50 nm)/FeNi(5 nm) sample measured between T = 2 K and 20 K and the corresponding calculated results of HE (b) and HC (d) for the SG/FM bilayers obtained between T = 2.6 K and 19.96 K.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562234&req=5

f3: Cooling field influence on the temperature dependent HE (a) and HC (c) for a Fe11Au89(50 nm)/FeNi(5 nm) sample measured between T = 2 K and 20 K and the corresponding calculated results of HE (b) and HC (d) for the SG/FM bilayers obtained between T = 2.6 K and 19.96 K.
Mentions: Experimental study of the HFC dependent EB has been performed and representative results are presented in Fig. 3. As displayed in Fig. 3(a,c), when HFC increases from 0.2 kOe to 50 kOe, the HE ∼ T curve shifts toward upper-left while the HC ∼ T curves keep almost overlapped. Accordingly, T0 decreases from 5.5 K to 4.2 K. The peak position of the HE ∼ T curve moves towards lower T slightly and the maximum positive value of HE increases significantly from 10 Oe to 18 Oe. Figure 3(b,d) show the corresponding simulation results. The sign inversion in HE with T can be reproduced and HE ∼ T curve shift can also be repeated. It is noticed that simulated T0, TP, and HE(TP) results have certain deviation from the experiments, but the theoretical HE ∼ T curves agree well with experimental measurements. On the other hand, the calculated trend of HC versus T is different from the experimental results obtained both by Ali et al.21 and us, but in agreement with those reported in ref. 22. Another disagreement with the present experimental results is that the theoretical HC ∼ T curves are HFC-dependent at the temperatures just below TB, i.e., HC for larger HFC is slightly larger. These discrepancies will be addressed later.

Bottom Line: Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards.In the meanwhile, HFC variation has weak effects on HC.Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.

ABSTRACT
We report on the experimental and theoretical studies of cooling field (HFC) and temperature (T) dependent exchange bias (EB) in FexAu1-x/Fe19Ni81 spin glass (SG)/ferromagnet (FM) bilayers. When x varies from 8% to 14% in the FexAu1-x SG alloys, with increasing T, a sign-changeable exchange bias field (HE) together with a unimodal distribution of coercivity (HC) are observed. Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards. In the meanwhile, HFC variation has weak effects on HC. By Monte Carlo simulation using a SG/FM vector model, we are able to reproduce such HE dependences on T and HFC for the SG/FM system. Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

No MeSH data available.


Related in: MedlinePlus