We have observed a weak transition in the dc susceptibility of Nd2Ru2O7 at 21 K. However, this transition is absent in the heat capacity data, indicating the absence of any structural or phase transition. We think that this transition is due to the canting of ferromagnetic component of Nd3+ spins. To confirm any change in magnetic structure of Ru4+ spins around 21 K, we have performed neutron scattering measurements at above (25 K) and below (18 K) the transition temperature. Now, as we observed there is change in the intensity of the magnetic peaks, we normalized the intensity at 25 K w.r.t. the intensity at 18 K and obtained difference spectra I(18K) - I_normalized (25 K). We did not observe any magnetic peak in the difference spectra. Therefore, we conclude that there is no change in the magnetic structure of Ru4+ spins around 21 K.
Now I want to know do the canting of spins would produce additional magnetic peaks in the neutron spectra at 18 K?
Should have been we observed additional magnetic peaks in the difference spectra I(18K) - I_normalized (25 K)?
Please suggest.
In general you would expect additional magnetic peaks only in a primitive ferromagnet, where additional AFM interaction leads to a canting. A canting of an AFM strucutre will lead to intensity changes (most likely, you get additional intensity on k=0, 0, 0); again this is a very general answer. In your case please have a look at J. Phys.: Condens. Matter
25 (2013) 186004; they attribute the observed transition to a parasitic phase Nd3RuO7 which can create a signal in your macroscopic measurements, but might be too small (wt.%) to be observed with neutrons.
@Matthias Frontzek.....The synchrotron studies of our samples has ruled out the possibility of parasitic phase Nd3RuO7.The Ru4+ spins are ordered antiferromagnetically below 146 K and Nd3+ spins are paramagnetic down to 1.8 K. As we have AFM structure, does that mean we would see only intensity changes and no additional magnetic peaks?
Could you please suggest me some reference regarding this?
We have also observed exchange interaction between Nd3+ and Ru4+ spins.
Thanks.
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