Do you think of a universal tilt angle with same orientation in the whole sample? Then any method you can apply with varying the angle should be able to help you. As an example, take low temperature magnetic isotherms (M(H) curves) as a function of sample tilt and model the resulting curves appropriately.

Alternatively, FMR is aboutthe most sensitive method to detect anisotropies and can be applied as a functin of field direction (see the linked paper for an example of thin films [50nm thickness, 5x5mm^2]).

But there may be a diffeent kind of such anisoropy (easy cone), where the azimutal orientation of the magnetization is arbitrary. Might not be too different in practice (never have dealt with this myself), but it's not the same thing.

What makes you think you have a tilted anisotropy axis?

Article Composition dependence of exchange stiffness in FexPt1-x alloys

Yes, as explained by Kai, the angle dependence of magnetization will tell you the easy axis. If the film is too thin and the magnetic moment can not be measured by VSM you may use magnetooptical Kerr effect.

Hi Kai,

thanks for your suggestions.  the system we are working is Pt/Co/Pt trilayers structure. we have a thickness gradient in the Co film.  [ Cobalt thickness gradient of : 44nm to 50nm linear variation of thickness over a 10mm distance along one direction of the film {say X axis} ].  Now for a PMA film (Co ~ 0.5nm) thickness we expect the same thickness gradient. We also have dependence of PMA on Co thickness (below spin reorientation transition).

Now in our case 2 possibilities arises because of the thickness gradient

1) Gradient in anisotropy

2) Tilt in anisotropy.

our doubt is whether both are related to each other or not ?

we got one reference: 'Slant-perpendicular magnetic anisotropy axis induced by steps in 4°-miscut Si/Cu/Au/Co/Au'    http://journals.aps.org/prb/abstract/10.1103/PhysRevB.69.134402

 We have LMOKE set up with 0.5T magnet. The sample can be titlted from inplane direction by angular resolution of 0.1degree.  We tried similar experiments ,but we could not find any signatures of titled PMA in our sample

Can you please suggest what all are the effect of graded film growth (the different magnetic properties that are affected) ?

In ultra thin layers and MLs the surface anisotopry produces the perpenidcular easy axix. This surface anisotropy goes as 1/t. there fore if there is a gradient in thickness (t) there is bound to be a large variation in Ku.