For nanomagnetic particles amount of heating depends on square of the applied field as well as frequency of the field. Unless both are not proper heating will not be generated. By increasing the current if field is not increased then probably additional increase in current may be used in generating Joule heat. have you checked? In that case ,cooling the coil may help. You may have to aware of additional losses due to Eddy current as well as resonance losses.

I have made an arrangement for circulating cool water (26 deg. cels.) through the coil. Hence, the coil is not over heating. I will check the other two and get back to you sir.

Actually the problem is that I am not being able to increase the current itself.

If you cannot increase the current then nothing may be wrong with your coil. It may be due to limitation of your current supply generator. Please check the rating of power supply and apply simple circuit equations.

Good luck.

Hi,

designing a suitable system is not so simple sometimes, the current will depend upon the quality of simple things like connections, capacitor specifications, quality/efficiency of the tank circuit, at higher frequencies the current flow will always be lower, inductance of the coil and many other factors.

For a few ideas please see the link below.

http://www.azonano.com/article.aspx?ArticleID=3853

I am agree with Mr. Rasbindu. You need to change the power supply. And use a  generator with higher current value but be careful, high currents can damage your device.

I am looking for some one who has such instruments and is interested to have collaboration with me on this field!