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4143 - Metamagnetism in self-assembled FeRh nanomagnets

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7 months 2 weeks ago #540 by jserra
Oral Presentation
Friday, December 11
Speaker: Lucie Motycková
Full Title: Metamagnetism in self-assembled FeRh nanomagnets

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7 months 1 week ago - 7 months 1 week ago #604 by PhiSimUniBasForum
Thank you for the nice talk!

I have a few questions for you:

1) You showed the island's magnetization as a function of temperatrue down to 100K. Do you have an idea, what would happen under further cooling, say, down to cryogenic temperatures? Is there another transition at some point, or will it just stay the same?

2) Are the islands single christal particles? Or are they composed of a number of smaller particles? If so, do you know in which way they order?

3) For the dewetting procedure, the islands turned antiferromagnetic after cooling to a certain temperature. Maybe i missed it, but is that due to a structural transition of the material? Or where does that come from?

4) Do you know which kind of magnetic anisotropies are involved?

Thank you in advance!
Last edit: 7 months 1 week ago by PhiSimUniBasForum.
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7 months 1 week ago #633 by Lucie Motyčková
Hello, thank you very much for the questions!

1) No, there is not any other transition upon further cooling. Below 100 K, magnetization stays rather constant or it slightly increases which could be due to (i) temperature increase of Ms where ferromagnetic order persists (interface with the substrate, surface layer, ...) or (ii) blocking of tiny superparamagnetic islands in the nanometer range that we rarely see with AFM.

2) Yes, we think they are nearly single crystal or very well textured. We have X-ray diffraction data confirming this.

3) Yes, there is a first-order antiferromagnetic-ferromagnetic transition which has an associated abrupt lattice parameter change, but the magnetostructural transition is isostructural (cubic to cubic).

4) For FeRh, the easy axes are the principal crystallographic axes, [100], [010], ...
However, in a previous report, a strain-dependent reorientation transition was also found (see Bordel et al., PRL 109, 117201 (2012)). In our case, shape anisotropy plays an important role as well.

Thank you for your interest!
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7 months 1 week ago #658 by PhiSimUniBasForum
Thank you for your answers :-)

And sorry for the late reation.

This sounds quite interesting. In the group i'm working in (Poggio Lab, Uni Basel, Switzerland), we have the possibility to measure magnetic properties (Phase transitions, reversal processes, switching events, anisotropy, etc) on very small samples using cantilever torque magnetometry. I was thinking perhaps we could remove one of the islands from the substrate using a micro manipulator and put it on a torque sensor. Would it be of any interest for you to have such information about single islands instead of whole samples? If yes, maybe we can talk about weather this would be feasible or not.

Have a nice day!

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7 months 1 day ago #663 by Lucie Motyčková
I am also sorry for my late response.

Thank you very much for your proposition. It indeed sounds interesting - I will discuss it with my colleagues.

I wish you a nice day.

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