It's not a law.
Materialism and Atheism don't necessarily have anything to do with each other; theistic materialism exists, and the materialism part is still the same (it's incidental that there is or isn't a god involved).
See "What is Materialism?" to better understand that part.
There is none!
No. Materialism is the idea that everything is either made only of matter or is dependent upon matter for its existence. It is possible for a philosophy to be materialistic and still accord a place to spirit, but most forms of materialism tend to reject the existence of spirit or anything non-physical. That last category would be atheistic materialism. Since atheistic materialism is not a thing made from matter, it's rather an idea and we don't think of ideas as being able to reproduce themselves. They are carried forward in the thoughts of subsequent generations of thinkers.
Materialism in its strictest sense refers to a world view according to which matter is the sole reality, and all things, beings and processes can be explained and accounted for in terms of material reality and phenomenon. Theism stands for belief in a supreme Being or God who is distinct or other from material reality, and is the cause or creator of matter. Paul Tillich, American theologian, probably, would say that God is Being-itself, or that God is the power of being, and ground of being of both material and non-material reality. Spinoza identified universe and nature with God. Hindu philosophy of advaita monism looks at material reality as an illusion. Theistic materialism would claim that matter is real, not an illusion, but it has been created by a superior reality of the Spirit. Matter can be controlled to manifest and incarnate the beauty of God. The terms 'atheistic materialism' and 'theistic materialism' have been used in philosophy. See, e.g., Robert C. Koons writes, "Philosophically, theistic materialism is a more coherent position than atheistic materialism, for the theist has an explanation for the three central facts that atheistic materialists must accept as brute facts." Koons, Robert C. Science and Theism: Concord not Conflict. http://www.utexas.edu/cola/depts/philosophy/faculty/koons/science.pdf., p.19. (Accessed on 21 September, 2007.) Another interseting book that has been recently published and which speaks on this topic is: Theistic Dialectical Materialism by James Singh, published at lulu.com. Atheistic materialists would deny the existence of God. Theistic materialism believes in God's existence, and claims that matter is subordinate to God,s purposes. The present writer encourages you to look for the terms 'Christian materialism' and 'theistic evolution' in Wikipedia. By J Chrysostom
Of or pertaining to materialism or materialists; of the nature of materialism.
The book Materialism was written by Jorie Graham.
Materialism should have material and physical possessions
Denial of materialism
Hylephobia is the name of the phobia related to the fear of materialism
Christianity looks down on materialism as an obstacle to spirituality.
Materialism in the relative sense is understood by Buddhists. Attachment and aversion to materialism is likely to lead to suffering as with any other composite phenomena.
Materialism is the self-indulgent pursuit of acquiring possessions to the exclusion of helping others in need.
Buddhism.