I get the hysteresis loops of FeCo HEA using the Vibrating Sample Magnetometry (VSM) to measure the coercivity. I use Quantum Design Magnetic Property Measurement System (MPMS) equipped with a standard Vibrating Sample Magnetometry (VSM) option. To improve the accuracy of data, I calibrated the device using a Pd standard sample and reset the magnet before each test. However, the hysteresis loops is shift a little to lefe side. Why? Can I get the coercivity on average？
Dear Sir,
I think the material you are studied is not perfectly pure. A manometric antiferromagnetic phase is probably present in the major FeCo ferromagnetic phase. Because of this antiferromagnetic phase, the coercivities measured in increasing and decreasing fields may be unequal as a result of the exchange bias.
For illustration purposes you can consult at:
https://hal.science/hal-00801706
a publication related to nano composites of iron and iron oxides, which display exchange bias fields. The bibliography associated to the paper could also help you.
Best regards.
Philippe.
sometimes the shifting occur in Mh loops of magnetic samples becase of exchange bias effect. however if there is no such kind of effect then it might be cause of measurement error. To remove the measurement error and make MH loops more symmetric, its better to find the difference between Hc on both side, divide by 2 and add the difference to magnetic field column.
Muhammad Arif Thank you for your answer. Do you think the shift of hysteresis loops influence the Hc ？and what kind of measurement error will induce its shift?
Yes, in case of assymetric MH loop the value of Hc can be different on both sides. However if MH loops is symmetric then you can find same value of Hc on both sides. it might occur becase of background signal.