Please recall the definition of magnetic susceptibility: it is equal to dM/dH. Of course, susceptibility is a function of temperature, but to calculate it you need M(H), not M(T).
Dear Professor Gutowski,
I have measured the magnetization (M) varying temperature at a fixed field of 1000 Oe. Now I want a curie plot (chi vs T). That means I am asking how to convert a M(T) plot to a chi(T) plot. Please answer.
Thanks and regards
I see. What you need is static susceptibility \chi, defined by relation M = \chi*H, not the more often used dynamic susceptibility I mentioned earlier. Yet even in this case my first comment is still applicable: there is now way to evaluate \chi from your measurements. But what you really want is Curie plot. Its purpose is to find critical temperature, TC , rather than the numerical values of \chi(T). Curie law states that M=C/(T-TC), where C is known as Curie constant. It is easy to see that your data points should form a straight line when plotted in coordinates (x,y) (T, M-1 ) as 1/M = T/C - TC/C. Intersection of this line and x-axis will tell you what is the value of TC. More precisely, you will see the straight line only for pure paramagnets (TC equal to zero, exactly), in any other case the straight line should be taken as a high-temperature asymptote of original data. The sign of so obtained TC will suggest you whether your sample is ferromagetic (TC>0) or antiferromagnetic (TC negative and usually renamed to TN - Neel temperature).
Dear Professor Gutowski,
Your information is really helpful. Although I have found a step by step procedure in the supplementary material of a research paper: Dalton Trans., 2009, 2467-2469.
Thanks & regards
Dear Dr. Gutowski,
As indicated magnetic susceptibility is a proportionality constant that indicates the degree of magnetization of a material in response to an applied magnetic field.
Is it possible to deduct/calculate susceptibility from M(H) loops? how?
Considering we have ascending and descending loops, at any field we have two numbers for the magnetization, one on the ascending loop and the other on the descending loop. Which one should be considered?
I greatly appreciate it if you could explain these for me.
@Shanti: I read the article you referenced (http://pubs.rsc.org/en/content/articlepdf/2009/dt/b819977a) but it does not address how to measure/calculate susceptibility.
@ Shanti did you perform the experiment with solid sample? How did you find out the magnetization/ change in magnetization? How to know which value of temperature to use?
Can you share how you have calculated?
@Amir Aslani: Your question is troublesome. The easy answer is: it doesn't matter when you investigate very soft magnetic materials. In this case both branches of hysteresis loop practically coincide and the problem disappears, exactly like in dia- or paramagnetic materials.
But how do you measure magnetic susceptibility in other cases? Usually the sample is placed in slowly varying uniform magnetic field which is at the same time modulated with small amplitude sinusoidal addition. A coil records response of this system. Now everything depends on earlier magnetic history of your sample. Things are pretty easy when your measurements were started from saturated state. Then, more or less, we are traveling along upper or lower branch of major hysteresis loop, respectively. Of course, this is only the approximation as in reality the magnetization of a sample changes by tracing a small minor loop. What you record is then the average signal originating from its two nearly identical branches.
I am unable to seriously interpret results taken for the sample when you start with H=0 and the so called demagnetized sample (i.e. when investigating virgin curve).
Dear Dr. Aslani,
It is given in the supplementary material. Please go through the link below:
http://www.rsc.org/suppdata/dt/b8/b819977a/b819977a.pdf
Thanks & regards,
Shanti
Dear Rudra Da,
I will send you the copy via email very soon.
Thanks & regards,
What conlusions can be drawn about the magnetic behavior of the complex from the graphs...plzz help
Dear Patra sir
Plzz give explain in details and also give relevant reference..plzz