"proper sphere" is a correct and usable phrase in written English.
It is typically used to refer to the area or domain in which something or someone operates or has jurisdiction. Example: The management consultant advised the company to focus on improving quality control within its proper sphere of production rather than trying to expand into unrelated industries.
Uplift, not political relevance, was art's proper sphere.
Color — apart from its proper sphere in painting — was deemed philosophically base and socially uncouth.
However, participants strongly disagreed about what exactly constitutes the private sector and what its proper sphere of responsibility should be.
Yet within government's proper sphere of action, he said Republicans have to be the "initiators of new ideas".
Mrs Thatcher regarded this – as her successors still do – as beyond their proper sphere, and did not hesitate to tell them so.
"You may pluck a fowl's wing-joints as bare as a pumpkin, but you will not erase from his memory that he is a fowl, and that his proper sphere is the open air," she warns.
Taylor seemed to have scrambled the normal relations among logic, language and the physical world, detaching them from their proper spheres.
Between his terms as Bundespräsident, he headed the Department of Justice, where his decisions helped define the proper spheres of federal and cantonal power.
In Locke's Letter Concerning Toleration, he develops several lines of arguments that are intended to establish the proper spheres for religion and politics.
The "domestic sphere" was women's proper domain.
Due to the advantages of the fabrication method, the CPO with area of larger than 1 can can be easily achieved, and their chiroptical resonance also can be expediently tuned in the infrared and visible region through using proper micro-sphere array and deposition parameters, such as deposition time, angle, and thickness.
